The secret vote that elected Pope Gregory X lasted from November 1268 to September 1271. It was the first example of a papal election by “compromise,” after a long struggle between supporters of two main geopolitical medieval factions — those faithful to the papacy and those supporting the Holy Roman Empire.

Fans of the Oscar-nominated movie “Conclave,” which is about a papal election, might think they have a head start on what’s to come next week. But