diff --git a/src/api/endpoints/class-tainacan-rest-filters-controller.php b/src/api/endpoints/class-tainacan-rest-filters-controller.php
index 702879823..ff46d15ea 100644
--- a/src/api/endpoints/class-tainacan-rest-filters-controller.php
+++ b/src/api/endpoints/class-tainacan-rest-filters-controller.php
@@ -136,25 +136,25 @@ class REST_Filters_Controller extends REST_Controller {
 			$metadatum_id      = $request['metadatum_id'];
 
 			$filter_obj->set_collection_id( $collection_id );
-			$filter_obj->set_metadatum( $metadatum_id );
+			$filter_obj->set_metadatum_id( $metadatum_id );
 		} elseif (isset($request['collection_id'])){
 			$collection_id = $request['collection_id'];
 
 			$filter_obj->set_collection_id( $collection_id );
 
-			if(!isset($body['metadatum'])){
+			if(!isset($body['metadatum_id'])){
 				throw new \InvalidArgumentException('You need provide a metadatum id');
 			}
 
-			$filter_obj->set_metadatum($body['metadatum']);
+			$filter_obj->set_metadatum_id($body['metadatum_id']);
 		} else {
 			$filter_obj->set_collection_id( 'filter_in_repository' );
 
-			if(!isset($body['metadatum'])){
+			if(!isset($body['metadatum_id'])){
 				throw new \InvalidArgumentException('You need provide a metadatum id');
 			}
 
-			$filter_obj->set_metadatum($body['metadatum']);
+			$filter_obj->set_metadatum_id($body['metadatum_id']);
 		}
 
 		$filter_obj->set_filter_type($filter_type);
diff --git a/src/api/endpoints/class-tainacan-rest-metadata-controller.php b/src/api/endpoints/class-tainacan-rest-metadata-controller.php
index e26bfdfe8..45a3569e7 100644
--- a/src/api/endpoints/class-tainacan-rest-metadata-controller.php
+++ b/src/api/endpoints/class-tainacan-rest-metadata-controller.php
@@ -288,9 +288,10 @@ class REST_Metadata_Controller extends REST_Controller {
 			$item_arr['metadata_type_object'] = $item->get_metadata_type_object()->_toArray();
 
 			if(isset($item_arr['metadata_type_options']) && isset($item_arr['metadata_type_options']['taxonomy_id'])){
-				$taxonomy = new Entities\Taxonomy($item_arr['metadata_type_options']['taxonomy_id']);
-
-				$item_arr['metadata_type_options']['taxonomy'] = $taxonomy->get_db_identifier();
+				$taxonomy = Repositories\Taxonomies::get_instance()->get_db_identifier_by_id( $item_arr['metadata_type_options']['taxonomy_id'] );
+				//$taxonomy = new Entities\Taxonomy($item_arr['metadata_type_options']['taxonomy_id']);
+				//$item_arr['metadata_type_options']['taxonomy'] = $taxonomy->get_db_identifier();
+				$item_arr['metadata_type_options']['taxonomy'] = $taxonomy;
 			}
 			
 			if($request['context'] === 'edit'){
diff --git a/src/classes/entities/class-tainacan-filter.php b/src/classes/entities/class-tainacan-filter.php
index fd6a8f0c0..75015a5dd 100644
--- a/src/classes/entities/class-tainacan-filter.php
+++ b/src/classes/entities/class-tainacan-filter.php
@@ -16,6 +16,7 @@ class Filter extends Entity {
         $order,
         $color,
         $metadatum,
+        $metadatum_id,
         $max_options,
         $filter_type,
         $filter_type_options;
@@ -40,7 +41,7 @@ class Filter extends Entity {
 	 */
 	public function _toArray(){
 		$filter_array = parent::_toArray();
-		$metadatum_id = $filter_array['metadatum'];
+		$metadatum_id = $filter_array['metadatum_id'];
 		$metadatum = $this->get_metadatum();
 
 		$filter_array['metadatum'] = [];
@@ -106,14 +107,33 @@ class Filter extends Entity {
     }
 
 	/**
-	 * Return the metadatum
+	 * Return the metadatum ID
 	 *
-	 * @return Metadatum
+	 * @return integer Metadatum ID
+	 */
+    function get_metadatum_id() {
+        return $this->get_mapped_property('metadatum_id');
+    }
+    
+    /**
+	 * Return the metadatum object
+	 *
+	 * @return Metadatum | null
 	 * @throws \Exception
 	 */
     function get_metadatum() {
-        $id = $this->get_mapped_property('metadatum');
-        return new Metadatum( $id );
+        if (isset($this->metadatum)) {
+            return $this->metadatum;
+        }
+        $id = $this->get_metadatum_id();
+        return new Metadatum($id);
+        $metadatum = \Tainacan\Repositories\Metadata::get_instance()->fetch((int) $id);
+        if ($metadatum instanceof Metadatum) {
+            $this->metadatum = $metadatum;
+            return $metadatum;
+        } else {
+            return null;
+        }
     }
 
     /**
@@ -192,15 +212,27 @@ class Filter extends Entity {
     }
 
     /**
-     * Define the filter metadatum
+     * Define the filter metadatum passing an object
      * 
      * @param \Tainacan\Entities\Metadatum
      * @return void
      */
-    function set_metadatum( $value ){
-    	$id = ( $value instanceof Metadatum ) ? $value->get_id() : $value;
+    function set_metadatum( \Tainacan\Entities\Metadatum $value ){
+    	$id = $value->get_id();
 
-        $this->set_mapped_property('metadatum', $id);
+        $this->set_metadatum_id($id);
+        $this->metadatum = $value;
+    }
+    
+    /**
+     * Define the filter metadatum passing an ID
+     * 
+     * @param int $value the metadatum ID
+     * @return void
+     */
+    function set_metadatum_id( $value ){
+        unset($this->metadatum);
+        $this->set_mapped_property('metadatum_id', $value);
     }
 
     /**
diff --git a/src/classes/filter-types/checkbox/class-tainacan-checkbox.php b/src/classes/filter-types/checkbox/class-tainacan-checkbox.php
index 1e2befc3d..1354eff94 100644
--- a/src/classes/filter-types/checkbox/class-tainacan-checkbox.php
+++ b/src/classes/filter-types/checkbox/class-tainacan-checkbox.php
@@ -64,8 +64,7 @@ class Checkbox extends Filter_Type {
 
     public function render( $filter ){
         return '<tainacan-filter-checkbox name="'.$filter->get_name().'"
-                                        filter_type="'.$filter->get_metadatum()->get_metadata_type().'"
                                         collection_id="'.$filter->get_collection_id().'"
-                                        metadatum_id="'.$filter->get_metadatum()->get_id().'"></tainacan-filter-selectbox>';
+                                        metadatum_id="'.$filter->get_metadatum_id().'"></tainacan-filter-selectbox>';
     }
 }
\ No newline at end of file
diff --git a/src/classes/filter-types/numeric/class-tainacan-numeric.php b/src/classes/filter-types/numeric/class-tainacan-numeric.php
index 9d266b3e4..abd2ae8a8 100644
--- a/src/classes/filter-types/numeric/class-tainacan-numeric.php
+++ b/src/classes/filter-types/numeric/class-tainacan-numeric.php
@@ -89,7 +89,7 @@ class Numeric extends Filter_Type {
                                         step="' . $this->get_option('step') . '" 
                                         name="'.$filter->get_name().'"
                                         collection_id="'.$filter->get_collection_id().'"
-                                        metadatum_id="'.$filter->get_metadatum()->get_id().'"></tainacan-filter-custom-interval>';
+                                        metadatum_id="'.$filter->get_metadatum_id().'"></tainacan-filter-custom-interval>';
     }
 
 
diff --git a/src/classes/filter-types/selectbox/class-tainacan-selectbox.php b/src/classes/filter-types/selectbox/class-tainacan-selectbox.php
index e83fdcad0..a9cc6bbc3 100644
--- a/src/classes/filter-types/selectbox/class-tainacan-selectbox.php
+++ b/src/classes/filter-types/selectbox/class-tainacan-selectbox.php
@@ -32,8 +32,7 @@ class Selectbox extends Filter_Type {
 
     public function render( $filter ){
         return '<tainacan-filter-selectbox name="'.$filter->get_name().'"
-                                        filter_type="'.$filter->get_metadatum()->get_metadata_type().'"
                                         collection_id="'.$filter->get_collection_id().'"
-                                        metadatum_id="'.$filter->get_metadatum()->get_id().'"></tainacan-filter-selectbox>';
+                                        metadatum_id="'.$filter->get_metadatum_id().'"></tainacan-filter-selectbox>';
     }
 }
\ No newline at end of file
diff --git a/src/classes/filter-types/taginput/class-tainacan-taginput.php b/src/classes/filter-types/taginput/class-tainacan-taginput.php
index e9ba673d2..518c5dd03 100644
--- a/src/classes/filter-types/taginput/class-tainacan-taginput.php
+++ b/src/classes/filter-types/taginput/class-tainacan-taginput.php
@@ -62,8 +62,7 @@ class Taginput extends Filter_Type {
 
     public function render( $filter ){
         return '<tainacan-filter-taginput name="'.$filter->get_name().'"
-                                        filter_type="'.$filter->get_metadatum()->get_metadata_type().'"
                                         collection_id="'.$filter->get_collection_id().'"
-                                        metadatum_id="'.$filter->get_metadatum()->get_id().'"></tainacan-filter-taginput>';
+                                        metadatum_id="'.$filter->get_metadatum_id().'"></tainacan-filter-taginput>';
     }
 }
\ No newline at end of file
diff --git a/src/classes/filter-types/taxonomy/class-tainacan-taxonomycheckbox.php b/src/classes/filter-types/taxonomy/class-tainacan-taxonomycheckbox.php
index 40691f32a..9070a8c42 100644
--- a/src/classes/filter-types/taxonomy/class-tainacan-taxonomycheckbox.php
+++ b/src/classes/filter-types/taxonomy/class-tainacan-taxonomycheckbox.php
@@ -64,8 +64,7 @@ class TaxonomyCheckbox extends Filter_Type {
 
     public function render( $filter ){
         return '<tainacan-filter-taxonomy-checkbox name="'.$filter->get_name().'"
-                                        filter_type="'.$filter->get_metadatum()->get_metadata_type().'"
                                         collection_id="'.$filter->get_collection_id().'"
-                                        metadatum_id="'.$filter->get_metadatum()->get_id().'"></tainacan-filter-taxonomy-checkbox>';
+                                        metadatum_id="'.$filter->get_metadatum_id().'"></tainacan-filter-taxonomy-checkbox>';
     }
 }
\ No newline at end of file
diff --git a/src/classes/filter-types/taxonomy/class-tainacan-taxonomytaginput.php b/src/classes/filter-types/taxonomy/class-tainacan-taxonomytaginput.php
index e63ea0097..158751856 100644
--- a/src/classes/filter-types/taxonomy/class-tainacan-taxonomytaginput.php
+++ b/src/classes/filter-types/taxonomy/class-tainacan-taxonomytaginput.php
@@ -62,8 +62,7 @@ class TaxonomyTaginput extends Filter_Type {
 
     public function render( $filter ){
         return '<tainacan-filter-taxonomy-taginput name="'.$filter->get_name().'"
-                                        filter_type="'.$filter->get_metadatum()->get_metadata_type().'"
                                         collection_id="'.$filter->get_collection_id().'"
-                                        metadatum_id="'.$filter->get_metadatum()->get_id().'"></tainacan-filter-taxonomy-taginput>';
+                                        metadatum_id="'.$filter->get_metadatum_id().'"></tainacan-filter-taxonomy-taginput>';
     }
 }
\ No newline at end of file
diff --git a/src/classes/repositories/class-tainacan-filters.php b/src/classes/repositories/class-tainacan-filters.php
index ae803ebce..53a9c3268 100644
--- a/src/classes/repositories/class-tainacan-filters.php
+++ b/src/classes/repositories/class-tainacan-filters.php
@@ -80,10 +80,10 @@ class Filters extends Repository {
 				'description' => __( 'Filter color', 'tainacan' ),
 				'validation'  => ''
 			],
-			'metadatum'           => [
+			'metadatum_id'           => [
 				'map'         => 'meta',
 				'title'       => __( 'Metadata', 'tainacan' ),
-				'type'        => 'array/object/string',
+				'type'        => 'integer',
 				'description' => __( 'Filter metadata', 'tainacan' ),
 				'validation'  => ''
 			],
diff --git a/src/migrations.php b/src/migrations.php
index b00a0bef9..3aab96a54 100644
--- a/src/migrations.php
+++ b/src/migrations.php
@@ -338,6 +338,16 @@ class Migrations {
 		flush_rewrite_rules(false);
 	}
 	
+	static function update_filters_definition() {
+		global $wpdb;
+		
+		$wpdb->query("UPDATE $wpdb->postmeta SET meta_key = 'metadatum_id' WHERE
+			meta_key = 'metadatum' AND post_id IN (
+				SELECT ID FROM $wpdb->posts WHERE post_type = 'tainacan-filter'
+			)");
+		
+	}
+	
 }
 
 
diff --git a/tests/test-api-filters.php b/tests/test-api-filters.php
index 87f0bcd1e..4d494dc18 100644
--- a/tests/test-api-filters.php
+++ b/tests/test-api-filters.php
@@ -70,8 +70,6 @@ class TAINACAN_REST_Terms_Controller extends TAINACAN_UnitApiTestCase {
 			)
 		);
 
-		$filter_type = $this->tainacan_filter_factory->create_filter('custom_interval');
-
 		$filter = $this->tainacan_entity_factory->create_entity(
 			'filter',
 			array(
@@ -79,7 +77,7 @@ class TAINACAN_REST_Terms_Controller extends TAINACAN_UnitApiTestCase {
 				'collection'  => $collection,
 				'description' => 'descricao',
 				'metadatum'    => $metadatum,
-				'filter_type' => $filter_type,
+				'filter_type' => 'Tainacan\Filter_Types\Custom_Interval',
 			),
 			true
 		);
@@ -296,7 +294,7 @@ class TAINACAN_REST_Terms_Controller extends TAINACAN_UnitApiTestCase {
 				'description' => 'Description of 2x Filter',
 				'status'      => 'publish'
 			],
-			'metadatum'       => $metadatum2->get_id()
+			'metadatum_id'       => $metadatum2->get_id()
 		]);
 
 		$filter_attr2 = json_encode([
@@ -306,7 +304,7 @@ class TAINACAN_REST_Terms_Controller extends TAINACAN_UnitApiTestCase {
 				'description' => 'Description of 4x Filter',
 				'status'      => 'publish'
 			],
-			'metadatum'       => $metadatum->get_id()
+			'metadatum_id'       => $metadatum->get_id()
 		]);
 
 		#### CREATE A FILTER IN REPOSITORY ####
diff --git a/tests/test-filters.php b/tests/test-filters.php
index e638ec929..395c4ecb0 100644
--- a/tests/test-filters.php
+++ b/tests/test-filters.php
@@ -65,7 +65,6 @@ class Filters extends TAINACAN_UnitTestCase {
 		    true
 	    );
 
-	    $filter_list_type = $this->tainacan_filter_factory->create_filter('selectbox');
 
 	    $filter = $this->tainacan_entity_factory->create_entity(
 	    	'filter',
@@ -74,7 +73,7 @@ class Filters extends TAINACAN_UnitTestCase {
 			    'collection'         => $collection,
 		    	'description' => 'descricao',
 			    'metadatum'           => $metadatum,
-			    'filter_type' => $filter_list_type
+			    'filter_type' => 'Tainacan\Filter_Types\Selectbox'
 		    ),
 		    true
 	    );
@@ -89,9 +88,8 @@ class Filters extends TAINACAN_UnitTestCase {
         $this->assertEquals( 'filtro', $test->get_name() );
         $this->assertEquals( $collection->get_id(), $test->get_collection_id() );
         $this->assertEquals( $metadatum->get_id(), $test->get_metadatum()->get_id() );
-        $objClass = get_class( $filter_list_type );
         $storedObjClass = get_class( $test->get_filter_type_object() );
-        $this->assertEquals($objClass , $storedObjClass );
+        $this->assertEquals('Tainacan\Filter_Types\Selectbox' , $storedObjClass );
 
     }
 
@@ -131,8 +129,6 @@ class Filters extends TAINACAN_UnitTestCase {
             true
         );
 
-        $autocomplete = $this->tainacan_filter_factory->create_filter('autocomplete');
-
         $filter = $this->tainacan_entity_factory->create_entity(
             'filter',
 	        array(
@@ -140,7 +136,7 @@ class Filters extends TAINACAN_UnitTestCase {
 		        'collection'  => $collection,
 		        'description' => 'descricao',
 		        'metadatum'       => $metadatum2,
-		        'filter_type' => $autocomplete
+		        'filter_type' => 'Tainacan\Filter_Types\Autocomplete'
 	        ),
             true
         );
@@ -149,14 +145,12 @@ class Filters extends TAINACAN_UnitTestCase {
 
         $this->assertEquals( 'Tainacan\Filter_Types\Autocomplete', $test->get_filter_type());
 
-        $custom_interval = $this->tainacan_filter_factory->create_filter('custom_interval');
-
         $filter2 = new \Tainacan\Entities\Filter();
         $filter2->set_name('filter 2');
         $filter2->set_collection($collection);
         $filter2->set_description('description');
         $filter2->set_metadatum($metadatum2);
-        $filter2->set_filter_type($custom_interval);
+        $filter2->set_filter_type('Tainacan\Filter_Types\Custom_Interval');
 
         $this->assertFalse($filter2->validate(), 'filter with a metadatum with unsupported primitive type should not validate');
 
@@ -186,7 +180,7 @@ class Filters extends TAINACAN_UnitTestCase {
 	        	'name'              => 'filter default',
 		        'collection_id'     => 'filter_in_repository',
 		        'filter_type'  => 'Tainacan\Filter_Types\Selectbox',
-				'metadatum'    => $meta_repo->get_id(),
+				'metadatum_id'    => $meta_repo->get_id(),
 		        'status'            => 'publish'
 	        ),
 	        true
@@ -216,7 +210,7 @@ class Filters extends TAINACAN_UnitTestCase {
 	        	'name'              => 'filter grandfather',
 		        'collection_id'     => $collection_grandfather->get_id(),
 		        'filter_type'  => 'Tainacan\Filter_Types\Selectbox',
-				'metadatum'    => $meta_grand->get_id(),
+				'metadatum_id'    => $meta_grand->get_id(),
 		        'status'            => 'publish'
 	        ),
 	        true
@@ -247,7 +241,7 @@ class Filters extends TAINACAN_UnitTestCase {
 	        	'name'              => 'filter father',
 		        'collection_id'     => $collection_father->get_id(),
 		        'filter_type'  => 'Tainacan\Filter_Types\Selectbox',
-				'metadatum'    => $meta_father->get_id(),
+				'metadatum_id'    => $meta_father->get_id(),
 		        'status'            => 'publish'
 	        ),
 	        true
@@ -281,7 +275,7 @@ class Filters extends TAINACAN_UnitTestCase {
 	        	'name'              => 'filter son',
 		        'collection_id'     => $collection_son->get_id(),
 		        'filter_type'  => 'Tainacan\Filter_Types\Selectbox',
-				'metadatum'    => $meta_son->get_id(),
+				'metadatum_id'    => $meta_son->get_id(),
 		        'status'            => 'publish'
 	        ),
 	        true
@@ -295,5 +289,82 @@ class Filters extends TAINACAN_UnitTestCase {
         $this->assertEquals( 4, sizeof( $retrieve_filters ) );
 		$this->assertEquals( 4, sizeof( $retrieve_filters_ids ) );
     }
+    
+    function test_metadatum_getter_setter(){
+        $Tainacan_Filters = \Tainacan\Repositories\Filters::get_instance();
+
+        $collection = $this->tainacan_entity_factory->create_entity(
+            'collection',
+            array(
+                'name'        => 'Collection filtered',
+                'description' => 'Is filtered',
+            ),
+            true
+        );
+
+        $metadatum2 = $this->tainacan_entity_factory->create_entity(
+            'metadatum',
+            array(
+                'name'          => 'Other filtered',
+                'description'   => 'Is filtered',
+                'metadata_type'    => 'Tainacan\Metadata_Types\Text',
+                'collection_id' => $collection->get_id()
+            ),
+            true
+        );
+
+        $filter2 = new \Tainacan\Entities\Filter();
+        $filter2->set_name('filter 2');
+        $filter2->set_collection($collection);
+        $filter2->set_description('description');
+        $filter2->set_metadatum($metadatum2);
+        $filter2->set_filter_type('Tainacan\Filter_Types\Selectbox');
+        
+        $filter2->validate();
+        
+        $filter = $Tainacan_Filters->insert($filter2);
+        
+        $this->assertEquals($metadatum2->get_id(), $filter->get_metadatum_id());
+        $this->assertEquals($metadatum2->get_name(), $filter->get_metadatum()->get_name());
+        
+        
+        $filter3 = new \Tainacan\Entities\Filter();
+        $filter3->set_name('filter 3');
+        $filter3->set_collection($collection);
+        $filter3->set_description('description');
+        $filter3->set_metadatum_id($metadatum2->get_id());
+        $filter3->set_filter_type('Tainacan\Filter_Types\Selectbox');
+        
+        $filter3->validate();
+        
+        $filter = $Tainacan_Filters->insert($filter3);
+        
+        $this->assertEquals($metadatum2->get_id(), $filter->get_metadatum_id());
+        $this->assertEquals($metadatum2->get_name(), $filter->get_metadatum()->get_name());
+        
+        $metadatum3 = $this->tainacan_entity_factory->create_entity(
+            'metadatum',
+            array(
+                'name'          => 'Other filtered',
+                'description'   => 'Is filtered',
+                'metadata_type'    => 'Tainacan\Metadata_Types\Text',
+                'collection_id' => $collection->get_id()
+            ),
+            true
+        );
+        
+        $filter4 = new \Tainacan\Entities\Filter();
+        $filter4->set_name('filter 4');
+        
+        $filter4->set_metadatum_id($metadatum3->get_id());
+        $this->assertEquals($metadatum3->get_id(), $filter4->get_metadatum_id());
+        $this->assertEquals($metadatum3->get_name(), $filter4->get_metadatum()->get_name());
+        
+        $filter4->set_metadatum($metadatum2);
+        $this->assertEquals($metadatum2->get_id(), $filter4->get_metadatum_id());
+        $this->assertEquals($metadatum2->get_name(), $filter4->get_metadatum()->get_name());
+        
+        
+    }
 	
 }
\ No newline at end of file