diff --git a/src/core/main.py b/src/core/main.py
index a3867c8..b83600b 100644
--- a/src/core/main.py
+++ b/src/core/main.py
@@ -657,8 +657,10 @@ def main():
                 raise
 
         for namespace in configuration.evaluateXpath("yep:namespace"):
-            ns = namespaces.Namespace(namespace.prop("name"), namespace.prop("uri"))
-            application.xpathContext.xpathRegisterNs(ns.name, ns.uri)
+            name, uri = namespace.prop("name"), namespace.prop("uri")
+            if not namespaces.getUri(name):
+                ns = namespaces.Namespace(name, uri)
+            application.xpathContext.xpathRegisterNs(name, uri)
 
         allVirtualHosts = [
             virtualHost for virtualHost in configuration.getVirtualHosts()]