The fourth son of Commander John Harris Nicolas
RN (1758–1844) and Margaret (née Blake), he was born at
Dartmouth. He was the brother of Rear Admiral
John Toup Nicolas RN CB KH; 1st Lt
Paul Harris Nicolas RM; and Lt Keigwin Nicholas RN. Having served in the navy from 1812 to 1816, he studied law and was called to the bar at the
Inner Temple in 1825. His work as a
barrister was confined principally to
peerage cases before the
House of Lords, and he devoted the rest of his time to the study of
genealogy and history. In 1831, he was made a
knight of the
Royal Guelphic Order, and, in 1832, chancellor and Knight Commander of the
Order of St Michael and St George (KCMG), being advanced to Grand Cross of the order in 1840. He became a member of the council of the
Society of Antiquaries in 1826, but soon began to criticise the management of the Society's affairs, and withdrew in 1828. He criticised the
Record Commission, which he regarded as too expensive. These attacks, which brought him into controversy with
Francis Palgrave, led in 1836 to the appointment of a select committee to inquire into the public records. Nicolas was also responsible for several reforms at the
British Museum. In 1822, he married Sarah (d. 1867), daughter of John Davison of
Loughton, Essex, a reputed descendant of the Tudor statesman
William Davison. They had two sons and six daughters. Financial difficulties compelled Nicolas to leave England, and he died near
Boulogne. ==Works==