What events shaped its early growth?

Thirteen years of persecution in Mecca, the migration to Medina, a handful of mostly defensive battles — and a peaceful return to Mecca, where the Prophet ﷺ pardoned the very people who had persecuted him.

Ancient materialism; the scientific revolution's mechanical picture of nature; Enlightenment criticism of religion — Hume's skepticism, and d'Holbach's openly atheist books; Darwin's theory of evolution (1859) offering a natural account of apparent design; then 19th–20th-century secular movements and state atheism in communist countries.

Ancient Greek skepticism (Pyrrho, Sextus Empiricus); Hume's and Kant's arguments that ultimate questions outrun human knowledge; and the Victorian science-and-religion debates, in which Huxley offered the term as a method: do not claim certainty you cannot show.

The disciples' proclamation that Jesus had risen; Paul's missionary journeys across the Roman world; the destruction of the Jerusalem Temple (70 CE), which hastened the separation from Judaism; waves of Roman persecution; then Constantine's conversion and the Edict of Milan (313 CE) legalizing the faith.

The exodus narrative and the giving of the Law; the kingdom and the First Temple; the Babylonian exile (586 BCE) and the return; the Second Temple period; and after the Temple's destruction (70 CE), the rebuilding of Jewish life around Torah study, the synagogue, and the rabbis.

The Buddha's awakening and forty-five years of teaching; the founding of the monastic order (sangha); the early councils that recited and organized his teaching after his death; and Emperor Ashoka's patronage (3rd century BCE), which carried the message across India and beyond.

The Vedic ritual religion; the Upanishads' turn inward toward Brahman and the self (c. 800–300 BCE); the great epics — the Mahabharata with the Bhagavad Gita, and the Ramayana; and the rise of devotion (bhakti) to Vishnu, Shiva, and the Goddess.

Nanak's message of one formless God beyond caste and empty ritual; nine successor Gurus building the community; conflict with the Mughal empire — two Gurus were executed — which shaped a defensive, martial identity; and Guru Gobind Singh's founding of the Khalsa order (1699).

Europe's wars of religion, which pressed the case for a state neutral between faiths; Enlightenment arguments for toleration; the US First Amendment (1791); the French separation law (1905); and the spread of these constitutional models through the colonial and post-colonial world.

The Renaissance recovery of classical learning; Enlightenment confidence in reason and rights; 19th-century ethical societies; and, after the world wars, the restatement of human dignity without appeal to God — the manifestos, and the founding of the international humanist body (1952).

England's 1688 revolution and the toleration debates; the American (1776) and French (1789) revolutions, which turned rights-talk into constitutions; the 19th-century struggles for free trade, free press, and the vote; and Mill's harm principle (1859) defining liberty's limits.

Enlightenment rights language applied to women; the anti-slavery movement, which trained a generation of women organizers; industrialization changing women's work and education; and the long suffrage campaigns — New Zealand granted the vote first, in 1893.

The French Revolution making 'the nation' sovereign; Napoleon's wars spreading — and provoking — national feeling across Europe; Romanticism (Herder) exalting language and folk culture; and print, mass schooling, and conscription binding strangers into one imagined people.