When Edward fled to Flanders in 1470 , Henry VI was re-installed Change_of_leadership as king on 3 October 1470 , but his resumption of rule was short lived , and he was deposed Change_of_leadership again following the defeat of his forces at the Battle of Tewkesbury , and on 21 May 1471 , Edward entered London unopposed , resumed Process_start the throne , and probably had Henry killed Killing that same day .