Portuguese Jesuit priest Melchior Miguel Carniero Leitão was appointed Titular Bishop of Nicaea on January 23, 1555. A year later (on January 26, 1576), Pope Gregory XIII issued an edict for the establishment of the Roman Catholic Diocese of Macau, where Leitão served—he was appointed the first bishop of Macau, a position he occupied till 1581.
No bishop of the diocese had been appointed archbishop or cardinal until Eugénio de Trigueiros and José da Costa Nunes were appointed as archbishops, following a re-designation by the Pope.
All Catholic bishops are appointed by the Pope, and are considered to be messengers (successors of the Apostles) as defined in the catechism of the Catholic Church;.
The Bishop of Macau is appointed as the spokesman of the Pope. He is the leader of the Roman Catholic Church in Macau, which he administers on behalf of the Pope. He is also responsible for the pastoral and charitable work that is carried out within the Diocese.。
Initially, the jurisdiction of the Bishop of Macau included China, Japan, Hong Kong, the Korean Peninsula and neighbouring areas. However, with development and the increasing need for pastoral work, the Vatican has since established more than 600 other Roman Catholic dioceses in the region. Presently, the Diocese has jurisdiction over six parishes and three quasi-parishes in the Macau Peninsula, Taipa and Coloane.