The Battle of Alnwick (1174) is one of two battles fought near the town of Alnwick, in Northumberland, England, the battle, which occurred on 13 July 1174, William I of Scotland, also known as William the Lion, was captured by a small English force led by which Chief Justiciar of England during the reign of King Henry II (1154–89) and was the probable author of "Tractatus de legibus et consuetudinibus regni Anglie"?