An area in the London Borough of Lewisham.
Blackheath contains one of the largest areas of common land in Greater London.
The name is recorded in 1166 as Blachehedfeld and means the "dark coloured heathland". It is formed from the Old English 'blæc' and 'hǣth' and refers to the open space that was the meeting place of the ancient hundred of Blackheath.
Blackheath was a rallying point for Wat Tyler's Peasants' Revolt of 1381, and for Jack Cade's Kentish rebellion in 1450. Wat Tyler is remembered by Wat Tyler Road on the heath. After pitching camp on Blackheath, Cornish rebels were defeated in the Battle of Deptford Bridge (sometimes called the Battle of Blackheath), just to the west, on 17 June 1497.
More information on the Wikipedia page