diff --git a/source/include/hierarchies/Hierarchies.hpp b/source/include/hierarchies/Hierarchies.hpp
index 5739b16..36c05c3 100644
--- a/source/include/hierarchies/Hierarchies.hpp
+++ b/source/include/hierarchies/Hierarchies.hpp
@@ -8,6 +8,8 @@
 #pragma once
 
 namespace himalaya {
+namespace hierarchies {
+
 namespace Hierarchies {
 
 /// Hierarchy numbers
@@ -67,4 +69,5 @@ namespace MassSchemes{
    };
 }
 
+} // namespace hierarchies
 } // namespace himalaya