francis cohen was born in london, the son of meyer cohen, a jewish stockbroker (d. 1831) by his wife rachel levien cohen (d. 1815). he was initially articled as a clerk to a london solicitor's firm, and remained there as chief clerk until 1822. his father was financially ruined in 1810 and francis, the eldest son, became responsible for supporting his parents. around 1814, francis cohen began contributing to the "edinburgh review"; he made the acquaintance of the banker dawson turner and his daughter elizabeth in 1819, offering to correct the proofs of turner's "architectural antiquities of normandy". in 1821, francis cohen was admitted to the fellowship of the royal society, one of his sponsors being turner. cohen converted to anglican christianity before his marriage to elizabeth turner on 13 october 1823.