Lancaster had been a supporter of Edward II, but like many within the realm he was angered by the kings reliance on his favourites, namely Piers Gaveston. Lancaster was among a number of men who were intent of seeing off Gaveston, they succeeded in 1312, when he was executed near Kenilworth in Warwickshire, on land belonging to Lancaster. Gaveston's death is thought to be at the top of the list of reasons as to why Lancaster was executed.
Thomas of Lancaster would not be the last to meet his death because he was prepared to stand up to a weak monarch who was influenced by others, Richard Fitz Alan, one of the founding members of the Lords Appellant was executed in 1397 for standing up to Richard II and Richard Duke of York's revenge death in 1460 is another example.
Lancaster has been called a