The papal conclave of 2013 was convened to elect a pope, the leader of the Catholic Church, to succeed Benedict XVI following his resignation on 28 February 2013. According to the apostolic constitution Universi Dominici gregis, which governed the vacancy of the Holy See, only cardinals who had not passed their 80th birthdays on the day on which the Holy See fell vacant (in this case, those who were born on or after 28 February 1933) were eligible to participate in the conclave. Although not a formal requirement, the cardinal electors invariably elect the pope from among their number. The election is carried out by secret ballot (Latin: per scrutinium).