diff --git a/src/JsonSchema/Constraints/Drafts/Draft06/Draft06Constraint.php b/src/JsonSchema/Constraints/Drafts/Draft06/Draft06Constraint.php
index bd6efac6..79e0ee23 100644
--- a/src/JsonSchema/Constraints/Drafts/Draft06/Draft06Constraint.php
+++ b/src/JsonSchema/Constraints/Drafts/Draft06/Draft06Constraint.php
@@ -66,6 +66,10 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
         $this->checkForKeyword('pattern', $value, $schema, $path, $i);
     }
 
+    private const KEYWORD_SCHEMA_PROPERTIES = [
+        'ref' => ['$ref'],
+    ];
+
     /**
      * @param mixed $value
      * @param mixed $schema
@@ -73,9 +77,15 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
      */
     protected function checkForKeyword(string $keyword, $value, $schema = null, ?JsonPointer $path = null, $i = null): void
     {
-        $validator = $this->factory->createInstanceFor($keyword);
-        $validator->check($value, $schema, $path, $i);
+        foreach (self::KEYWORD_SCHEMA_PROPERTIES[$keyword] ?? [$keyword] as $property) {
+            if (property_exists($schema, $property)) {
+                $validator = $this->factory->createInstanceFor($keyword);
+                $validator->check($value, $schema, $path, $i);
+
+                $this->addErrors($validator->getErrors());
 
-        $this->addErrors($validator->getErrors());
+                return;
+            }
+        }
     }
 }
diff --git a/src/JsonSchema/Constraints/Drafts/Draft07/Draft07Constraint.php b/src/JsonSchema/Constraints/Drafts/Draft07/Draft07Constraint.php
index 084ce96c..d1cac103 100644
--- a/src/JsonSchema/Constraints/Drafts/Draft07/Draft07Constraint.php
+++ b/src/JsonSchema/Constraints/Drafts/Draft07/Draft07Constraint.php
@@ -68,6 +68,12 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
         $this->checkForKeyword('content', $value, $schema, $path, $i);
     }
 
+    private const KEYWORD_SCHEMA_PROPERTIES = [
+        'ref' => ['$ref'],
+        'ifThenElse' => ['if'],
+        'content' => ['contentMediaType', 'contentEncoding'],
+    ];
+
     /**
      * @param mixed $value
      * @param mixed $schema
@@ -75,9 +81,15 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
      */
     protected function checkForKeyword(string $keyword, $value, $schema = null, ?JsonPointer $path = null, $i = null): void
     {
-        $validator = $this->factory->createInstanceFor($keyword);
-        $validator->check($value, $schema, $path, $i);
+        foreach (self::KEYWORD_SCHEMA_PROPERTIES[$keyword] ?? [$keyword] as $property) {
+            if (property_exists($schema, $property)) {
+                $validator = $this->factory->createInstanceFor($keyword);
+                $validator->check($value, $schema, $path, $i);
+
+                $this->addErrors($validator->getErrors());
 
-        $this->addErrors($validator->getErrors());
+                return;
+            }
+        }
     }
 }
diff --git a/src/JsonSchema/Constraints/Drafts/Draft2019/Draft2019Constraint.php b/src/JsonSchema/Constraints/Drafts/Draft2019/Draft2019Constraint.php
index 0b003b54..2167387e 100644
--- a/src/JsonSchema/Constraints/Drafts/Draft2019/Draft2019Constraint.php
+++ b/src/JsonSchema/Constraints/Drafts/Draft2019/Draft2019Constraint.php
@@ -69,6 +69,12 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
         $this->checkForKeyword('content', $value, $schema, $path, $i);
     }
 
+    private const KEYWORD_SCHEMA_PROPERTIES = [
+        'ref' => ['$ref'],
+        'ifThenElse' => ['if'],
+        'content' => ['contentMediaType', 'contentEncoding'],
+    ];
+
     /**
      * @param mixed $value
      * @param mixed $schema
@@ -76,9 +82,15 @@ public function check(&$value, $schema = null, ?JsonPointer $path = null, $i = n
      */
     protected function checkForKeyword(string $keyword, $value, $schema = null, ?JsonPointer $path = null, $i = null): void
     {
-        $validator = $this->factory->createInstanceFor($keyword);
-        $validator->check($value, $schema, $path, $i);
+        foreach (self::KEYWORD_SCHEMA_PROPERTIES[$keyword] ?? [$keyword] as $property) {
+            if (property_exists($schema, $property)) {
+                $validator = $this->factory->createInstanceFor($keyword);
+                $validator->check($value, $schema, $path, $i);
+
+                $this->addErrors($validator->getErrors());
 
-        $this->addErrors($validator->getErrors());
+                return;
+            }
+        }
     }
 }
diff --git a/tests/Constraints/Drafts/Draft06/Draft06ConstraintTest.php b/tests/Constraints/Drafts/Draft06/Draft06ConstraintTest.php
new file mode 100644
index 00000000..ed6d9842
--- /dev/null
+++ b/tests/Constraints/Drafts/Draft06/Draft06ConstraintTest.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace JsonSchema\Tests\Constraints\Drafts\Draft06;
+
+use JsonSchema\Constraints\BaseConstraint;
+use JsonSchema\Constraints\ConstraintInterface;
+use JsonSchema\Constraints\Drafts\Draft06\Draft06Constraint;
+use JsonSchema\Constraints\Factory;
+use PHPUnit\Framework\TestCase;
+
+class Draft06ConstraintTest extends TestCase
+{
+    public function testNoConstraintsAreInstantiatedForAnEmptySchema(): void
+    {
+        $constraint = new Draft06Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{}');
+        $value = json_decode('{}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame([], $calledKeywords);
+    }
+
+    public function testOnlyKeywordsPresentInSchemaAreInstantiated(): void
+    {
+        $constraint = new Draft06Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"type": "object", "required": ["id"]}');
+        $value = json_decode('{"id": 1}');
+        $constraint->check($value, $schema);
+
+        sort($calledKeywords);
+        $this->assertSame(['required', 'type'], $calledKeywords);
+    }
+
+    public function testRefKeywordIsInstantiatedWhenDollarRefPropertyIsPresent(): void
+    {
+        $constraint = new Draft06Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"$ref": "#/definitions/foo"}');
+        $value = json_decode('{}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['ref'], $calledKeywords);
+    }
+
+    private function createSpyFactory(array &$calledKeywords): Factory
+    {
+        $constraintStub = $this->createMock(ConstraintInterface::class);
+        $constraintStub->method('getErrors')->willReturn([]);
+
+        $factory = $this->createMock(Factory::class);
+        $factory->method('createInstanceFor')
+            ->willReturnCallback(static function (string $keyword) use (&$calledKeywords, $constraintStub) {
+                $calledKeywords[] = $keyword;
+
+                return $constraintStub;
+            });
+
+        return $factory;
+    }
+
+    private function injectFactory(Draft06Constraint $constraint, Factory $factory): void
+    {
+        $property = new \ReflectionProperty(BaseConstraint::class, 'factory');
+        if (PHP_VERSION_ID < 80100) {
+            $property->setAccessible(true);
+        }
+        $property->setValue($constraint, $factory);
+    }
+}
diff --git a/tests/Constraints/Drafts/Draft07/Draft07ConstraintTest.php b/tests/Constraints/Drafts/Draft07/Draft07ConstraintTest.php
new file mode 100644
index 00000000..a2ccb048
--- /dev/null
+++ b/tests/Constraints/Drafts/Draft07/Draft07ConstraintTest.php
@@ -0,0 +1,114 @@
+<?php
+
+declare(strict_types=1);
+
+namespace JsonSchema\Tests\Constraints\Drafts\Draft07;
+
+use JsonSchema\Constraints\BaseConstraint;
+use JsonSchema\Constraints\ConstraintInterface;
+use JsonSchema\Constraints\Drafts\Draft07\Draft07Constraint;
+use JsonSchema\Constraints\Factory;
+use PHPUnit\Framework\TestCase;
+
+class Draft07ConstraintTest extends TestCase
+{
+    public function testNoConstraintsAreInstantiatedForAnEmptySchema(): void
+    {
+        $constraint = new Draft07Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{}');
+        $value = json_decode('{}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame([], $calledKeywords);
+    }
+
+    public function testOnlyKeywordsPresentInSchemaAreInstantiated(): void
+    {
+        $constraint = new Draft07Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"type": "object", "required": ["id"]}');
+        $value = json_decode('{"id": 1}');
+        $constraint->check($value, $schema);
+
+        sort($calledKeywords);
+        $this->assertSame(['required', 'type'], $calledKeywords);
+    }
+
+    public function testRefKeywordIsInstantiatedWhenDollarRefPropertyIsPresent(): void
+    {
+        $constraint = new Draft07Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"$ref": "#/definitions/foo"}');
+        $value = json_decode('{}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['ref'], $calledKeywords);
+    }
+
+    public function testIfThenElseKeywordIsInstantiatedWhenIfPropertyIsPresent(): void
+    {
+        $constraint = new Draft07Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"if": {"type": "string"}}');
+        $value = json_decode('"hello"');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['ifThenElse'], $calledKeywords);
+    }
+
+    /**
+     * @dataProvider contentPropertyProvider
+     */
+    public function testContentKeywordIsInstantiatedWhenEitherContentPropertyIsPresent(string $property): void
+    {
+        $constraint = new Draft07Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode(sprintf('{"%s": "text/plain"}', $property));
+        $value = json_decode('"hello"');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['content'], $calledKeywords);
+    }
+
+    public static function contentPropertyProvider(): \Generator
+    {
+        yield 'contentMediaType' => ['contentMediaType'];
+        yield 'contentEncoding' => ['contentEncoding'];
+    }
+
+    private function createSpyFactory(array &$calledKeywords): Factory
+    {
+        $constraintStub = $this->createMock(ConstraintInterface::class);
+        $constraintStub->method('getErrors')->willReturn([]);
+
+        $factory = $this->createMock(Factory::class);
+        $factory->method('createInstanceFor')
+            ->willReturnCallback(static function (string $keyword) use (&$calledKeywords, $constraintStub) {
+                $calledKeywords[] = $keyword;
+
+                return $constraintStub;
+            });
+
+        return $factory;
+    }
+
+    private function injectFactory(Draft07Constraint $constraint, Factory $factory): void
+    {
+        $property = new \ReflectionProperty(BaseConstraint::class, 'factory');
+        if (PHP_VERSION_ID < 80100) {
+            $property->setAccessible(true);
+        }
+        $property->setValue($constraint, $factory);
+    }
+}
diff --git a/tests/Constraints/Drafts/Draft2019/Draft2019ConstraintTest.php b/tests/Constraints/Drafts/Draft2019/Draft2019ConstraintTest.php
new file mode 100644
index 00000000..4d11573e
--- /dev/null
+++ b/tests/Constraints/Drafts/Draft2019/Draft2019ConstraintTest.php
@@ -0,0 +1,127 @@
+<?php
+
+declare(strict_types=1);
+
+namespace JsonSchema\Tests\Constraints\Drafts\Draft2019;
+
+use JsonSchema\Constraints\BaseConstraint;
+use JsonSchema\Constraints\ConstraintInterface;
+use JsonSchema\Constraints\Drafts\Draft2019\Draft2019Constraint;
+use JsonSchema\Constraints\Factory;
+use PHPUnit\Framework\TestCase;
+
+class Draft2019ConstraintTest extends TestCase
+{
+    public function testNoConstraintsAreInstantiatedForAnEmptySchema(): void
+    {
+        $constraint = new Draft2019Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{}');
+        $value = json_decode('{}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame([], $calledKeywords);
+    }
+
+    public function testOnlyKeywordsPresentInSchemaAreInstantiated(): void
+    {
+        $constraint = new Draft2019Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"type": "object", "required": ["id"]}');
+        $value = json_decode('{"id": 1}');
+        $constraint->check($value, $schema);
+
+        sort($calledKeywords);
+        $this->assertSame(['required', 'type'], $calledKeywords);
+    }
+
+    public function testRefKeywordIsInstantiatedWhenDollarRefPropertyIsPresent(): void
+    {
+        $constraint = new Draft2019Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"$ref": "#/definitions/foo"}');
+        $value = json_decode('{}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['ref'], $calledKeywords);
+    }
+
+    public function testIfThenElseKeywordIsInstantiatedWhenIfPropertyIsPresent(): void
+    {
+        $constraint = new Draft2019Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"if": {"type": "string"}}');
+        $value = json_decode('"hello"');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['ifThenElse'], $calledKeywords);
+    }
+
+    /**
+     * @dataProvider contentPropertyProvider
+     */
+    public function testContentKeywordIsInstantiatedWhenEitherContentPropertyIsPresent(string $property): void
+    {
+        $constraint = new Draft2019Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode(sprintf('{"%s": "text/plain"}', $property));
+        $value = json_decode('"hello"');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['content'], $calledKeywords);
+    }
+
+    public static function contentPropertyProvider(): \Generator
+    {
+        yield 'contentMediaType' => ['contentMediaType'];
+        yield 'contentEncoding' => ['contentEncoding'];
+    }
+
+    public function testDependentSchemasAndDependentRequiredAreInstantiatedIndependently(): void
+    {
+        $constraint = new Draft2019Constraint();
+        $calledKeywords = [];
+        $this->injectFactory($constraint, $this->createSpyFactory($calledKeywords));
+
+        $schema = json_decode('{"dependentRequired": {"a": ["b"]}}');
+        $value = json_decode('{"a": 1, "b": 2}');
+        $constraint->check($value, $schema);
+
+        $this->assertSame(['dependentRequired'], $calledKeywords);
+    }
+
+    private function createSpyFactory(array &$calledKeywords): Factory
+    {
+        $constraintStub = $this->createMock(ConstraintInterface::class);
+        $constraintStub->method('getErrors')->willReturn([]);
+
+        $factory = $this->createMock(Factory::class);
+        $factory->method('createInstanceFor')
+            ->willReturnCallback(static function (string $keyword) use (&$calledKeywords, $constraintStub) {
+                $calledKeywords[] = $keyword;
+
+                return $constraintStub;
+            });
+
+        return $factory;
+    }
+
+    private function injectFactory(Draft2019Constraint $constraint, Factory $factory): void
+    {
+        $property = new \ReflectionProperty(BaseConstraint::class, 'factory');
+        if (PHP_VERSION_ID < 80100) {
+            $property->setAccessible(true);
+        }
+        $property->setValue($constraint, $factory);
+    }
+}