A cardinal warned that the pope’s top administrator was undermining his papacy. And two church benefactors sounded an alarm that the Vatican’s governing hierarchy, known as the Roman Curia, was riddled with intrigue. …

This is the Vatican inherited by Pope Francis, the former Cardinal Jorge Mario Bergoglio of Buenos Aires, who will be formally installed as pope on Tuesday. In his first week on the job he has shown an uncommon humility, signaling a new direction for the church. Yet, changing the style of the papacy is far easier than changing the Vatican — an ancient monarchy in which the pope is treated like a king, branches of the hierarchy are run like medieval fiefs and supplicants vie for access and influence.

For decades popes have tried, and often failed, to change the Vatican. How Francis fares could define his papacy — and determine whether the church can better serve its more than one billion faithful around the globe. …

As the head of the Catholic Church, Francis is more than its spiritual leader. He is also the top box of one of the most opaque government flow charts in the world, running the last truly global empire from the world’s smallest sovereign state, which sits on 108 acres in the heart of Rome behind high walls.