The Second Battle of St Albans was a battle of the English Wars of the Roses fought on 17 February 1461, at St Albans. The army of the Yorkist faction under the Earl of Warwick attempted to bar the road to London north of the town. The rival Lancastrian army used a wide outflanking manoeuvre to take Warwick by surprise, cut him off from London, and drive his army from the field. The victors also released the feeble King Henry VI, who had been Warwick's prisoner, from his captivity. However, they ultimately failed to take advantage of their victory.
More information on the Wikipedia page [1] and the Historic UK page [2].