Madog II ap Gruffydd, Lord of Dinas Bran

He supported the Prince of Wales, Llywelyn ap Gruffudd, who had married the daughter of Simon de Montfort, 6th Earl of Leicester.

He inherited the throne on the death of his father Prince Gruffydd Maelor II, and was the Lord of the Castle of Dinas Bran.

He was in alliance with Llywelyn ap Gruffudd, the prince of Gwynedd and all Wales as his effective overlord during the period following the Treaty of Montgomery.

In 1275, Llywelyn married the daughter of Simon de Montfort, 6th Earl of Leicester, the arch-enemy of the English king's father, Henry III.

When Llywelyn refused to offer a personal explanation, the king declared him a rebel and in 1277 invaded North Wales.