Also spelt Alasdair. Birth date approx. Son of Murdoch Stewart, 2nd Duke of Albany.
Murdoch, his sons Walter and Alexander, and Duncan, Earl of Lennox were in Stirling Castle for their trial on 18 May 1425, at a prorogued parliament in the presence of the King which heard the evidence that linked the prisoners to the rebellion in the Lennox—in a trial lasting just one day the four men were found guilty of treason.
Walter was condemned on 24 May. Murdoch and his son Alexander were tried before the same jury the following day. All the prisoners were publicly beheaded on Heading Hill "in front of" Stirling Castle.