REXML::XPath.first(document,"//*[name()='saml:AuthnStatement' or name()='saml2:AuthnStatement' or name()='AuthnStatement']/*[name()='saml:AuthnContext' or name()='saml2:AuthnContext' or name()='AuthnContext']/*[name()='saml:AuthnContextClassRef' or name()='saml2:AuthnContextClassRef' or name()='AuthnContextClassRef']/text()").to_s