The War of the Roses is partly adapted from a Shakespeare play that culminates in which opening battle of the war?
The Wars of the Roses (adaptation): The Wars of the Roses was a 1963 theatrical adaptation of William Shakespeare's first historical tetralogy ("1 Henry VI", "2 Henry VI", "3 Henry VI" and "Richard III"), which deals with the conflict between the House of Lancaster and the House of York over the throne of England, a conflict known as the Wars of the Roses. Henry VI, Part 2:  As such, the play culminates with the opening battle of the War, the First Battle of St Albans.
First Battle of St Albans