Kanishka was the third ruler of the Kushana empire. He was the grandson of Kadphises I, the founder of the Kushana empire. The famous Rabatak Inscription written on a rock in the Bactrian language and the Greek script presents valuable information on Kanishka.
Viharas were for the purpose of living, Chaityas were assemblies for the purpose of discussions. Further, Chaityas were with Stupas, Viharas did not have stupas.