Sir George Downing, 1st Baronet (c. 1625 – c. 19 July 1684) was an Anglo-Irish statesman, soldier, diplomat and spymaster and preacher, whose allegiances notably changed during his career, and after whom Downing Street in London is named.

Born in Dublin in 1625, he was the son of Emmanuel Downing, a barrister of the Inner Temple in London, himself the son of an Ipswich schoolmaster. Emmanuel was a Puritan who undertook missionary work, first in Ireland, and then (at the invitation of Massachusetts Bay Governor John Winthrop) in New England.

Downing Street is a 200-metre (660 ft) long street in the City of Westminster that houses the official residences and offices of the Prime Minister of the United Kingdom and the Chancellor of the Exchequer. Situated off Whitehall, a few minutes walk from the Houses of Parliament, Downing Street was built in the 1680s by Irishman Sir George Downing.

More Info: en.wikipedia.org