diff --git a/src/Header/GenericHeader.php b/src/Header/GenericHeader.php
index 945d8cfa..60df4fbc 100644
--- a/src/Header/GenericHeader.php
+++ b/src/Header/GenericHeader.php
@@ -84,7 +84,7 @@ public function setFieldName($fieldName)
         // Validate what we have
         if (!preg_match('/^[a-z][a-z0-9-]*$/i', $fieldName)) {
             throw new Exception\InvalidArgumentException(
-                'Header name must start with a letter, and consists of only letters, numbers and dashes.'
+                'Header name must start with a letter, and consist of only letters, numbers and dashes.'
             );
         }