Alexander Henderson, (born 1583?, Creich, Fife, Scot.—died Aug. 19, 1646, Edinburgh), Scottish Presbyterian clergyman primarily responsible for the preservation of the presbyterian form of church government in Scotland, who was influential in the defeat of the English king Charles I during the Civil War of 1642–51.
In 1612 Henderson was nearly prevented from assuming duties in Leuchars, Fife, by parishioners who were angered by his intransigence and unorthodoxy. Henderson soon adjusted to standard Presbyterian practice, however, and his pastorate remained uneventful for the next 25 years. Only through an ecclesiastical dispute in 1637 did he emerge from his role as a quiet, efficient country minister. Because he refused to procure copies for his parish of the newly issued book of canons (1636) and of a subsequent book of worship imposed by Charles I, he was summoned to Edinburgh. There he boldly defended his disobedience and gained recognition as a leader. Henderson was largely responsible for the resistance that found expression in the National Covenant of 1638, a Presbyterian statement that led to a general assembly of churchmen in Glasgow later that year.
Henderson furthered his reputation as a leader by his conduct as moderator of the assembly and was soon transferred to Edinburgh. He became the major figure in the negotiations following the two Bishops’ Wars, in which native Scottish bishops vied with English loyalists for control of the Church of Scotland. At the onset of the first war, he wrote the pamphlet Instructions for a Defensive Arms (1638), a justification of the people’s right to self-defense. Charles I lost his struggle to subordinate the Scottish Church to that of England, and in 1641 the presbyterian system was made secure in Scotland. For the next two years Henderson occupied himself with reorganization of the restored church.
With the outbreak of civil war in England in 1642, Henderson led the great majority of Scotsmen to side with the English Parliament against the King. Through the Solemn League and Covenant of 1643, the Scots committed military support on behalf of Parliament and won representation in the English assembly of Westminster, a religious body that advised Parliament. This assembly was commissioned to reconstitute church rule in the British Isles. With the Scottish clergymen Samuel Rutherford, Robert Baillie, and George Gillespie, Henderson engaged in preaching and propagandizing for the Church of Scotland in the Westminster Assembly.
Second only to John Knox (c. 1514–72) as a leader in the reformed Church of Scotland, Henderson was the author of numerous tracts, most effective among them being The Bishops’ Doom (1638) and The Government and Order of the Church of Scotland (1641), composed for the assembly at Westminster.