Throughout the 17th century, Reverend Shepard and his successors preached a
Calvinistic doctrine. In the 18th century, the ministers moved the theology in a more liberal direction. Specifically, Reverend
William Brattle and Reverend
Nathaniel Appleton amended their Calvinist preaching to encourage "free inquiry", and they held a tolerant and catholic spirit towards those who differed on doctrinal matters. Appleton's successor, Timothy Hilliard, was
Arminian rather than Calvinistic in theology. The division between Calvinists and Arminians, which appeared in many churches of the Standing Order in the 18th century, reached a time of crisis in the period from 1805 to 1830. The minister of the Cambridge church at that time was the Reverend
Abiel Holmes, the father of
Oliver Wendell Holmes. Reverend Holmes held to orthodox doctrinal views, but he remained on friendly terms with the liberal or Arminian party for three decades after his installation in 1792. In 1826, however, he decided to break off relations with the liberals, specifically abolishing pulpit exchanges with the liberal or Unitarian ministers. After vainly attempting to persuade Reverend Holmes to return to his earlier, more inclusive practices, the Parish voted to dismiss him as its public teacher of religion and morality. By 1829, most of the Parish became Unitarian. Dr. Holmes and the more conservative members of his flock departed and founded the Shepard
Congregational Society. In 1899, it was agreed that the church associated with that society should be called the First Church in Cambridge (Congregational), now part of the
United Church of Christ, and this church, the First Parish in Cambridge (Unitarian) [now Unitarian Universalist]. The Reverend William Newell, the church's first avowedly Unitarian minister, led the congregation from 1830 to 1868. His immediate successor,
Francis Greenwood Peabody, would become a leader of the
Social Gospel movement. The fourteenth minister, Reverend Dr.
Samuel McChord Crothers, an eloquent preacher and widely read essayist, managed to attract a following from both the University and the Old Cambridge communities. In 1837, Transcendentalist
Ralph Waldo Emerson delivered his now famous
"American Scholar" address—referred to by Oliver Wendell Holmes as America's "Intellectual Declaration of Independence"—at the First Parish Church. ==Present membership==