As Catholics around the world watch for white smoke above the papal conclave this week, speculation about the next pope’s choice for a holy moniker is heating up.

Bookies are even following the action, with popular Irish bookmaker Paddy Power offering 10/11 odds on Leo, 9/2 odds on Pius, and 6/1 odds on Gregory as of Tuesday afternoon.

The company is also offering fairly favorable odds on Peter, the original pope, but as the Economist notes, no one has yet dared take on Saint Peter’s legacy.

The practice of the pope choosing a name isn’t anything new, however.

Newly elected popes have been renaming themselves for centuries, with some historians dating the practice back to a 6th century pontiff whose real name was Mercurius, after the god Mercury.

“A pope named after a pagan god — that wasn’t going to go over, PR-wise,” historian Biagio Mazza told the Kansas City Star.

Mercurius promptly rechristened himself John II.morehere