Lord of the World is a 1907 dystopian science fiction novel by the English Catholic priest Robert Hugh Benson that centres upon the reign of the Antichrist, which is enabled by a movement towards global peace and the unification of religious and political thought. It has been called prophetic by Popes Benedict XVI, Francis, and Leo XIV.

In the early 21st-century, with the Tories (rebranded as "Individualists") in decline, the British Empire is functionally a one-party state. The British royal family has been deposed, and Esperanto is widely spoken. Marxism, atheism, liberalism and secular humanism dominate culture and politics.

The world now has only three main religious forces: Catholicism, Humanitarianism, and the Eastern religions. Humanitarianism is essentially atheism, but has adopted the creed that "God is Man." Rome was given entirely to the Pope, who then instituted the death penalty for offenses including adultery and apostasy. The world is otherwise divided into three superstates: a loosely organized European Confederation of socialist states and their colonies in Africa, bound together by Free Trade but on the verge of consolidating under a European parliament; the Eastern Empire, which includes Asia, Australia, and New Zealand; and the American Republic, consisting of both North and South America. The European Confederation and Eastern Empire are on the brink of war.

Oliver Brand, an influential MP from Croydon, is among the most ardent opponents of Catholicism. Oliver's wife Mabel witnesses a volor (flying transport) crash. As the government's Ministers of Euthanasia arrive and finish off the wounded, she sees a priest, Percy Franklin, give Last Rites to a dying Catholic. Traumatised by what she witnessed, Mabel tells Oliver that both the priest and the dying man seemed to believe in what they were doing. Oliver explains the Catholic belief in the afterlife in a dismissive way, and Mabel is mollified.

A mysterious Senator Felsenburgh unexpectedly takes charge of the American Republic's peace delegation and travels the Empire, delivering speeches to rapt audiences in their own languages. Due to Felsenburgh's efforts, world peace is secured. Oliver urges Mabel to accompany him to the announcement, where Felsenburgh will be. With them away, Oliver's secretary, Mr. Phillips, summons Franklin to the house. He explains that Oliver's elderly mother used to be Catholic and wishes to return to the Church before her imminent death. Franklin meets Mrs. Brand and receives her back into the Church. The Brands return home and find Franklin there. To Oliver's shock, Franklin appears physically identical to Felsenburgh. Mabel urges Franklin to leave in peace. She explains that he will see Felsenburgh and the overflowing joy that his arrival has occasioned. On his way home, Franklin encounters a rally being addressed by Felsenburgh. The priest is tempted to believe in him.

While Oliver is away, Mrs. Brand takes a turn for the worse. Ignoring Mabel's sermons against Christianity, Mrs. Brand pleads for Franklin to be summoned. Mabel has her involuntarily euthanised, knowing that Oliver would desire it.

Felsenburgh accepts the post of President of Europe. There is great rejoicing throughout Europe. The Cardinal Protector of England dies, and Franklin is chosen to succeed him. Under Franklin's recommendation, the pope creates an Order of Christ Crucified to spread Catholicism in the face of persecution, an order with no habit or badge, "freer than the Jesuits, poorer than the Franciscans, more mortified than the Carthusians". Many join the new order and are martyred throughout the world.

The Parliaments of Europe institute weekly Humanist ceremonies. Attendance is optional except for the four annual festivals of Maternity, Life, Sustenance, and Paternity. Oliver becomes Minister of Public Worship in England, planning the ceremonies with an ex-priest, John Francis.