After a high-profile university trial in Cambridge, which deprived him of his residency rights as fellow of his college, he became a leading figure in London radical circles.
His father intended him for business, and he was sent to Saint-Omer in the Pas-de-Calais to learn French, and then to a mercantile house (trading company) in Quebec, where he remained for a few weeks.
[2][3] At the end of 1780 he was admitted deacon in the Church of England, and advanced to the priesthood in 1783, when he was presented to the living of Madingley, near Cambridge, where he officiated zealously until June 1787.
At that time, candidates for the Master of Arts had to "subscribe to" (state their belief in—the literal meaning is "sign below") the Thirty-nine Articles, the historically defining statements of doctrines of the Church of England with respect to the controversies of the English Reformation.
Frend published his 'Address to the Inhabitants of Cambridge' in favour of his new creed, and he supported vigorously a proposal introduced into the senate house (i.e. the governing body of the university) on 11 December 1787 that would render this statement of belief no longer necessary.
[2] He took, in company with an old schoolfellow called Richard Tylden, a lengthy tour in France, the Low Countries, Germany, and Switzerland.
[2] In 1793 Frend wrote a tract entitled Peace and Union recommended to the Associated Bodies of Republicans and Anti-republicans, in which he denounced abuses and condemned much of the liturgy of the church of England.
An appeal against the sentence followed, and the university counsel including the barrister Simon Le Blanc became involved;[6] it was unanimously affirmed by the delegates on 29 June, and on 26 November 1795 the Court of King's Bench discharged a rule which Frend had obtained for restoring him to the franchises of a resident M.A.
280–309), reprints an account of the trial, and, while condemning the tone of the pamphlet, describes the proceedings as a party move and vindicates the tract from the accusation of sedition.
Augustus De Morgan wrote that chalked graffiti "Frend for ever" appeared; bishop-to-be Herbert Marsh was apprehended, while two other future establishment pillars, John Singleton Copley and William Rough escaped.
[13] Frend was one of the group of reformers who supported at this time the early activities of the Literary Fund set up by David Williams.
[2] He continued in radical activities, participating around 1810 in a fundraising committee, with Timothy Brown, John Cartwright, William Cobbett, and Robert Waithman, to support Gwyllym Lloyd Wardle.
Among Frend's pupils were Edward Daniel Clarke, Ada Lovelace, John Singleton Copley, and Robert Malthus; he was himself the last of "the learned anti-Newtonians and a noted oppugner of all that distinguishes Algebra from Arithmetic.
[7] Frend's Unitarian network, as well as the group round Priestley, included James Gifford the elder[18] and Robert Hibbert.
[20] He was frequently consulted by John Palmer in support of his claim for a public grant for his services in improving the transmission of letters.
Maseres in his Tracts on the Resolution of Cubick and Biquadratick Equations, published supplements to his appendix to Frend's Principles of Algebra.