Chichester, Arthur (1739–99), 5th earl and 1st marquess of Donegall , landlord, was born 13 June 1739, elder son of John Chichester (d. 1746), MP for Belfast, and Elizabeth Chichester (née Newdigate). He succeeded his uncle, Arthur Chichester, 4th earl of Donegall, in 1757, graduated MA from Oxford (1759), was appointed privy counsellor (1766), and was MP for Malmesbury 1768–74. He married (16 November 1761) Lady Anne Hamilton, daughter of the duke of Hamilton. They lived at Fisherwick Park, Staffordshire, England. In 1765 he visited the family's huge estates in and near Belfast, and from 1767 began to reallocate leases, demanding entry fines and increased rents from the new tenants; the money raised was used largely to develop and embellish the English estates. The earl's support for government was rewarded when he was created earl of Belfast and 1st marquess of Donegall on 4 July 1791. He was involved in 1786 in an acrimonious dispute over Belfast property with Barry Yelverton (qv); the marquess's workmen demolished improvements made by Yelverton, who was later obliged to sell his leasehold to the marquess. Though he lived mostly on his English estates, Donegall did devote some attention to Belfast's development, stipulating how new building should be carried out, and he also built the city's handsome exchange, assembly rooms, and parish church. He gave the land for the publicly funded Poor House and White Linen Hall, and spent the huge sum of £62,000 on completing the Lagan canal.
However, contemporaries judged him to be one of the worst absentee landlords, and his policies of estate management bear some blame for the outbreak in 1770 of the Hearts of Steel rebellion in Co. Antrim, and for the resulting upsurge in emigration to America. Though his Irish estates produced £48,000 annually, financial and family problems were compounded by the spectacular extravagance and incompetence of the 1st marquess's heir, George Augustus Chichester (qv), eldest of three sons of his first wife. She died after a long illness in 1780. The 1st marquess's later marriages were childless; on 24 October 1788, at Bath, he married Charlotte Moore, a widow from Co. Down, daughter of Conway Spencer, and in November 1790, in London, he married Barbara Godfrey, whose father was a Yorkshireman, but was rector of Midleton, Co. Cork; she was thirty years his junior. He died 5 January 1799.