The conservative had became one of Pope Francis ' most ardent critics and a symbol of the polarized Catholic Church in the United States and beyond.

While once enjoying support in the Vatican and U.S. church hierarchies, the Italian archbishop alienated many as he developed a fringe following while delving deeper into conspiracy theories on everything — from the coronavirus pandemic to what he called the "Great Reset" and Russia's war in Ukraine.

The Vatican's doctrine office announced the penalty after a meeting of its members on Thursday and informed Vigano of its decision on Friday.

It cited Vigano's public "refusal to recognize and submit to the Supreme Pontiff, his rejection of communion with the members of the church subject to him, and of the legitimacy and magisterial authority of the Second Vatican Council."

The excommunication, which Vigano incurred automatically with his positions, means he is formally outside communion with the church, and cannot celebrate or receive its sacraments. The crime of schism occurs when someone withdraws submission to the pope or from the communion of Catholics who are subject to him.

Unlike defrocking, a punitive measure that makes a priest a layman again, excommunication is considered a "medicinal" penalty and is declared in hope those who incurred it would repent and come back into communion. If that happens, the Holy See can lift the penalty.

Schisms, which have been regular in the church's 2,000-year history, are considered particularly dangerous as they threaten the unity of the church.

Vigano's dire pronunciations about the current state of the church, amplified on Catholic social media and by ideologically friendly bloggers on both sides of the Atlantic, were an exaggerated version of the chasm between U.S. ultra-conservatives and Francis. And while Vigano enjoyed mainstream support among bishops early in his career, many quietly distanced themselves as his ideas became more extreme.