White smoke from the Sistine Chapel on Thursday signaled that the cardinals have selected the next leader of the Catholic Church.

The first thing the new pope will do is choose a name. In the history of the papacy, the most commonly used name has been John, first chosen in 523 by Saint John I, the Vatican says. The last pope to choose that name was Italian Angelo Giuseppe Roncalli, elected Pope John XXIII, in 1958. Roncalli was proclaimed a saint by Pope Francis in 2014.

One hundred and thirty-three cardinals are sequestering themselves behind the Vatican’s medieval walls for the start of a conclave to elect a successor to Pope Francis.