Five centuries later, the ruling elite of the Khazar Khaganate, a Turkic confederacy straddling Asia and Europe, converted to Judaism. The past is another country, where one could encounter cultural interactions and melting pots that have slipped into obscurity. Now, a Mexican-origin singer who wears a turban has brought to light the ties that existed between two communities in California. In the early 1900s, many Punjabi men in California married Mexican women, and Talibelico, the singer, harks back to that past, although he doesn’t claim any such ancestry. Now, his Punjabi-Spanish fusion in collaboration with Harveer Singh — an immigrant from Jalandhar whose Spanish singing first drew Talibelico’s interest — is getting millions of views online.