Robert P. Molyneux SJ (July 24, 1738 – December 9, 1808)[b] was an English-American Catholic priest and Jesuit missionary to the United States.

Born to a prominent English family, he entered the Society of Jesus and studied at the College of St Omer in France.

[3][4] Due to the Penal Laws, he was tutored privately at home,[5] before entering the Society of Jesus on September 7, 1757, following in the path of his brother, William.

[10] With the outbreak of the American Revolutionary War in 1775, Molyneux adopted a personal policies described as general neutrality,[11] as well as moderate patriotism.

[3] Four members of the Continental Congress, including George Washington and John Adams, visited Old St. Joseph's during the war, and Molyneux celebrated the requiem masses for a French officer who drowned in the Schuylkill River and the Spanish ambassador.

[13] Molyneux supported the establishment of a Catholic episcopal hierarchy in the United States, so that it would be separate from the ecclesiastical jurisdiction of the English bishops.

[14] Molyneux then joined others in writing to Rome to request the elevation of the apostolic prefecture to the rank of diocese and the installation of an American bishop.

[4] He Molyneux tutored Anne-César de La Luzerne, the French minister plenipotentiary to the United States, in English.

[22] Molyneux immediately undertook a project to expand the college, purchasing two acres (0.81 hectares) of land,[23] located to the north of the original Old South building.

[24] Funding for construction of the building was unsteady,[25] as the school was unable to raise adequate money through donations by Maryland Catholics.

Compared to the small structures and simple architecture of the city at the time, Old North was monumental,[24] and was described as one of the "grandest works in Washington, after the Capitol Building.

"[26] In late 1796, Molyneux submitted his resignation to John Carroll because of his declining health; Louis William DuBourg was named as his successor in October of that year.

In response, the pope issued the bull Catholicæ Fidei on March 7, 1801, which officially permitted the Society of Jesus to continue existing in the Russian Empire.

They pope gave them verbal approval and expressed his desire for the worldwide restoration of the Jesuits, but did not commit this to writing, as the political enemies of the Society remained powerful.

[34] In addition to his duties as superior, Molyneux again resumed the presidency of Georgetown on October 1, 1806,[7] replacing Bishop Leonard Neale.

[38] Saint Joseph's University in Philadelphia created the Molyneux-Lilly Award, named for Robert Molyneux and Thomas Lilly, both Jesuits.