On April 29, 2014, Brian Mason announced that he would step down as leader as soon as a leadership election could be held to choose his successor. Mason who had mentored Rachel Notley convinced her to run for the leadership which she won. During the final few months of Mason's tenure the party was already enjoying strong polling in Edmonton, something which would eventually grow into the larger electoral sweep that the Alberta NDP managed in the 2015 provincial election under Mason's successor Notley that resulted in the formation of Alberta's first ever NDP government.