Question

Where and by whom was the first Buddhist Council convened? 

Answer 1

Most of the modern scholars agree that the first Buddhist Council was held around 400BC in Rajgriha, at Sattapanni caves to be precise. The Ajatasatru held the patronage but function of the president was taken by the monk Mahakasyapa.

Answer 2

The First Buddhist council was convened in the year following the Buddha's Parinibbana which is 543–542 BCE.