From the Wikipedia page 
Archibald Douglas, 5th Earl of Angus (1449 – October 1513), was a late medieval Scottish magnate. He became known as "Bell the Cat". He became the most powerful nobleman in the realm through a successful rebellion and established his family as the most important in the kingdom.
In 1481, Angus became Warden of the East March, but the next year he joined the league against James III and his favourite, Robert Cochrane, at Lauder. Here he is said earned his nickname by offering to "bell the cat"—specifically, to deal with Cochrane—beginning the attack upon him by pulling his gold chain off his neck, and then ordering the hanging of Cochrane and others of the king's favourites from Lauder old bridge (the site of which is in the grounds of Thirlestane Castle). The earliest written source for the story is in David Hume of Godscroft, the Douglas family biographer. The phrase "to bell the cat" comes from one of Aesop's fables, "The Mice in Council", and refers to a dangerous task undertaken for the benefit of all.
Subsequently he joined Alexander Stewart, Duke of Albany, in league with Edward IV of England on 11 February 1483, signing the convention at Westminster which acknowledged the overlordship of the English king. However, in March Albany and Angus returned, outwardly at least, to their allegiance, and received pardons for their treason.
After a period of peace between them, Angus and the king again started to quarrel. Angus now decided to rebel against the king. Having the support of the Scottish nobility this time, he marched against James III and they fought the Battle of Sauchieburn during which the king was killed.
Angus became one of the guardians of the young king James IV. but soon lost influence, to the Homes and Hepburns, and the wardenship of the marches went to Alexander Home. Though outwardly on good terms with James, Angus treacherously made a treaty with Henry VII around 1489 or 1491, by which he undertook to govern his relations with James according to instructions from England. He also agreed to hand over Hermitage Castle, commanding the pass through Liddesdale into Scotland, on the condition of receiving English estates in compensation.
In October 1491 he fortified his castle of Tantallon against James, but had to submit and to exchange his Liddesdale estate and Hermitage Castle for the lordship of Bothwell.
In 1493 Angus again returned to favour, receiving various grants of lands. He became Chancellor, which office he retained till 1498. In June 1497 he opened talks for the surrender of Perkin Warbeck at 'Jenyn Haugh'. In 1501, in disgrace once more, he was confined to Dumbarton Castle. At the disaster at Flodden Field in 1513, though absent himself, Angus lost his two eldest sons. As the Scottish nation licked its wounds, Angus won appointment as one of the councilors of Margaret Tudor the queen regent; but the newly appointed councilor died at the end of October 1513. His successor to the Earldom of Angus was his grandson, Archibald Douglas, 6th Earl of Angus.