Complex sentence: Qazan/Kazan was a choice name for the male Turkic/Mongol royalty, most notably that of the Ilkhanid Mongol king, Qazan Khan.
Split into simpler sentences: Qazan/Kazan was a choice name for the male Turkic/Mongol royalty. Most famously, that of the famous Ilkhanid Mongol king, Qazan Khan.