diff --git a/src/Xmlns.php b/src/Xmlns.php
index fc7f47d..9308990 100644
--- a/src/Xmlns.php
+++ b/src/Xmlns.php
@@ -27,4 +27,14 @@ public static function xsd(): XmlXmlns
     {
         return XmlXmlns::load('http://www.w3.org/2001/XMLSchema');
     }
+
+    public static function soap11Envelope(): XmlXmlns
+    {
+        return XmlXmlns::load('http://schemas.xmlsoap.org/soap/envelope/');
+    }
+
+    public static function soap12Envelope(): XmlXmlns
+    {
+        return XmlXmlns::load('http://www.w3.org/2003/05/soap-envelope/');
+    }
 }
diff --git a/tests/Unit/XmlnsTest.php b/tests/Unit/XmlnsTest.php
index 90436d5..7ce7cc5 100644
--- a/tests/Unit/XmlnsTest.php
+++ b/tests/Unit/XmlnsTest.php
@@ -24,19 +24,27 @@ public function provideKnownXmlnses()
     {
         yield 'wsdl' => [
             static fn () => Xmlns::wsdl(),
-            'http://schemas.xmlsoap.org/wsdl/'
+            'http://schemas.xmlsoap.org/wsdl/',
         ];
         yield 'soap' => [
             static fn () => Xmlns::soap(),
-            'http://schemas.xmlsoap.org/wsdl/soap/'
+            'http://schemas.xmlsoap.org/wsdl/soap/',
         ];
         yield 'soap12' => [
             static fn () => Xmlns::soap12(),
-            'http://schemas.xmlsoap.org/wsdl/soap12/'
+            'http://schemas.xmlsoap.org/wsdl/soap12/',
         ];
         yield 'xsd' => [
             static fn () => Xmlns::xsd(),
-            'http://www.w3.org/2001/XMLSchema'
+            'http://www.w3.org/2001/XMLSchema',
+        ];
+        yield 'envelope11' => [
+            static fn () => Xmlns::soap11Envelope(),
+            'http://schemas.xmlsoap.org/soap/envelope/',
+        ];
+        yield 'envelope12' => [
+            static fn () => Xmlns::soap12Envelope(),
+            'http://www.w3.org/2003/05/soap-envelope/',
         ];
     }
 }