diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 799126b..61971fe 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -502,15 +502,10 @@
         :param critical: Set to ``True`` if the extension must be understood and
              handled by whoever reads the certificate.
 
-    .. method:: sign(backend, private_key, algorithm)
+    .. method:: sign(private_key, algorithm, backend)
 
         Sign the certificate using the CA's private key.
 
-        :param backend: Backend that will be used to build the certificate.
-            Must support the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
-
         :param private_key: The
             :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`,
             :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey` or
@@ -521,6 +516,11 @@
             :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` that
             will be used to generate the signature.
 
+        :param backend: Backend that will be used to build the certificate.
+            Must support the
+            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
+            interface.
+
 
 X.509 CSR (Certificate Signing Request) Object
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/src/cryptography/x509.py b/src/cryptography/x509.py
index a831506..f35582b 100644
--- a/src/cryptography/x509.py
+++ b/src/cryptography/x509.py
@@ -1740,7 +1740,7 @@
             self._not_valid_after, self._extensions + [extension]
         )
 
-    def sign(self, backend, private_key, algorithm):
+    def sign(self, private_key, algorithm, backend):
         """
         Signs the certificate using the CA's private key.
         """
diff --git a/tests/test_x509.py b/tests/test_x509.py
index ac20f64..ba35f64 100644
--- a/tests/test_x509.py
+++ b/tests/test_x509.py
@@ -809,7 +809,7 @@
             not_valid_after
         )
 
-        cert = builder.sign(backend, issuer_private_key, hashes.SHA1())
+        cert = builder.sign(issuer_private_key, hashes.SHA1(), backend)
 
         assert cert.version is x509.Version.v3
         assert cert.not_valid_before == not_valid_before
@@ -969,7 +969,7 @@
         builder = x509.CertificateBuilder()
 
         with pytest.raises(TypeError):
-            builder.sign(backend, private_key, object())
+            builder.sign(private_key, object(), backend)
 
     @pytest.mark.requires_backend_interface(interface=DSABackend)
     @pytest.mark.requires_backend_interface(interface=X509Backend)
@@ -981,7 +981,7 @@
         builder = x509.CertificateBuilder()
 
         with pytest.raises(NotImplementedError):
-            builder.sign(backend, private_key, hashes.SHA512())
+            builder.sign(private_key, hashes.SHA512(), backend)
 
     @pytest.mark.requires_backend_interface(interface=EllipticCurveBackend)
     @pytest.mark.requires_backend_interface(interface=X509Backend)
@@ -994,7 +994,7 @@
         builder = x509.CertificateBuilder()
 
         with pytest.raises(NotImplementedError):
-            builder.sign(backend, private_key, hashes.SHA512())
+            builder.sign(private_key, hashes.SHA512(), backend)
 
     @pytest.mark.requires_backend_interface(interface=DSABackend)
     @pytest.mark.requires_backend_interface(interface=X509Backend)
@@ -1027,7 +1027,7 @@
             not_valid_after
         )
 
-        cert = builder.sign(backend, issuer_private_key, hashes.SHA1())
+        cert = builder.sign(issuer_private_key, hashes.SHA1(), backend)
 
         assert cert.version is x509.Version.v3
         assert cert.not_valid_before == not_valid_before
@@ -1076,7 +1076,7 @@
             not_valid_after
         )
 
-        cert = builder.sign(backend, issuer_private_key, hashes.SHA1())
+        cert = builder.sign(issuer_private_key, hashes.SHA1(), backend)
 
         assert cert.version is x509.Version.v3
         assert cert.not_valid_before == not_valid_before
@@ -1117,7 +1117,7 @@
         )
 
         with pytest.raises(ValueError):
-            builder.sign(backend, issuer_private_key, hashes.SHA512())
+            builder.sign(issuer_private_key, hashes.SHA512(), backend)
 
 
 @pytest.mark.requires_backend_interface(interface=X509Backend)