Combining multiple vocabularies without tears

Description:An important motivation for introducing namespaces to [Extensible Markup Language (XML) 1.0] is to combine markup from multiple vocabularies. However, [Namespaces in XML] provides unique names without addressing validation. Later, namespace-aware schema languages such as [RELAX NG] and [W3C XML Schema] have been developed. Schemas written in these languages can handle multi-namespace documents.