Alexander Irvine, 2nd Laird of Drum.  A newly-found charter establishes that his name was Alexander, and not "Sir Thomas or William" as give in previous genealogies.  He also held the lands of Forglen.  No evidence has been found concerning his wife, but she was probably a daughter of Fraser of Frendraught.  He died about 1380.

It was probably during the lifetime of William's son, Alexander, the 2nd laird, that the feud arose with near neighbours the Keiths, hereditary Marshals of Scotland. Legend has it that the Irvines burned down Halforest Castle, stronghold of the Keiths, in revenge for their burning to death in the fields one of the Irvine children. There was also a pitched battle at Keiths' Muir, near the Dee, in which many of the Keiths were drowned at a place called Keiths' Pot. One was cut down while clinging to a stone which occasionally still appears above the water and is known as Keiths' Stone.