Pope Leo XIV, the first American pope in history, was inaugurated at St. Peter's Square before an estimated 200,000 attendees, including world leaders, pilgrims, and clergy. The former Cardinal Robert Francis Prevost, the 267th Pope, emphasized unity and peace in his inaugural Mass.

The inauguration was attended by numerous heads of state, sovereigns, and religious representatives from various faiths. Prominent figures included President Bola Tinubu of Nigeria, Vice President JD Vance of the U.S., Ukrainian President Volodymyr Zelenskyy, and other global leaders. President Tinubu met with Peter Obi and former Governor Kayode Fayemi during the event, emphasizing unity in diversity for Nigeria's stability and development.

The installation Mass featured rich symbolism and global representation, beginning with a prayer at the tomb of St. Peter. The liturgy included readings in multiple languages, such as Spanish, Italian, English, and Latin, with the Gospel also sung in Greek to honor Eastern Catholic tradition. Pope Leo received the papal pallium and the fisherman’s ring, symbolizing his role as shepherd and leader of the Catholic Church. During his homily, Pope Leo expressed his commitment to serving the faithful through love and unity, aiming for the Church to be a force for peace in the world.

Pope Leo XIV addressed global challenges, including discord, hatred, violence, and economic exploitation. He called for collaboration among Christians, people of other faiths, and individuals of goodwill to build a peaceful world. Tinubu urged Nigerians to use their diversity for stability and development, highlighting the historic significance of his presence at the inauguration.

Pope Leo vowed to continue the legacy of Pope Francis on social issues, such as combating poverty and protecting the environment, while also preserving the Christian faith. He emphasized unity and harmony within the Church, addressing divisions between conservatives and progressives. He committed to serving the faith without being autocratic, walking alongside his brothers and sisters in Christ.

The inauguration included a popemobile tour through St. Peter’s Square, where Pope Leo blessed babies and greeted the crowds. He received symbolic items, including the pallium and the fisherman's ring. Since becoming Pope, Leo has highlighted priorities such as addressing the dangers of artificial intelligence and promoting global peace. He called for peace in Ukraine and addressed the humanitarian situation in Gaza, reflecting his commitment to addressing global conflicts and promoting unity within the Church.