The Young Pope

A young cardinal, Lenny Belardo, becomes pope of the Catholic Church when machinations of the leading contenders to gain the position themselves fail. He takes the name of Pius XIII and proceeds to challenge the established traditions and practices of the Vatican. He installs Sister Mary, the nun who raised him in an orphanage, to serve as his chief adviser. Driven by his desire to confront his parents, who abandoned him as a boy, Belardo takes the church in a new conservative direction, causing disruption inside and outside the Vatican. - Wikipedia