Ballymote castle was built around the year 1300 by the Anglo-Norman Richard de Burgo, second Earl of Ulster, who was known as the ‘Red Earl’ in order to protect his newly won possessions in Sligo. The site of the castle was known as Atha Cliath an Chorainn, the ford of the hurdles of Corran. He also built a road from Boyle to Collooney called the ‘Red Earl’s Road’. The old Ordnance Survey maps name the road through Roscrib as the Red Earl’s road.
The castle was possibly the strongest in Connacht at the time. The area within the walls is 150ft square. There was a formidable double towered gate in the centre of the north wall and subsidiary D-shaped towers in the centre of the East and West curtain walls. A postern gate planned for the centre of the south wall was never completed, probably because of the events os 1317, when the castle was lost to the O’Connors. The walls are about ten feet thick and flanked with six noble towers. Passages of about 3 feet wide ran through the centre of the walls all around and the passages were so constructed so that they gave access to the towers, and to the intervening curtains at different heights, and thus they met the need of attack or defence.

The castle changed hands many times down the years. It was captured by the O’Connors of Sligo in 1317, but was taken from them in the course of local struggles by the Mac Diarmada in 1347. By 1381 it had passed to the MacDonaghs. Although attached to Tadhg MacDiarmada in 1561, it had apparently passed to O’Conor Sligo by 1571,at which time he surrendered the castle and had it regranted to him by the English. In 1577 the castle fell into English hands for a few months, and then more permanently in 1584, when it was taken by the notorious govenor of Connaught, Richard Bingham. The O’Connors, O’Hartes and O’Dowds burned it in 1588. The English surrendered it in 1598 to the MacDonaghs who sold it shortly afterwards to the O’Donnells. It was from this castle that Red Hugh O’Donnell marched to the disastrous battle of Kinsale in 1601. When the O’ Donnells surrendered it to the English in 1602, it was already in a bad state of repair. In 1633 the Taaffes owned it for a short time, but had to surrender it again to the English Parliamentary forces in 1652.

In the Williamite wars the castle was held by Captain Terence MacDonagh for King James 11, but he had to surrender it to Lord Granard in the face of an artillery attack in 1690. Soon afterwards the fortifications were made harmless, the moat was filled up and the castle fell into ruins. Underground passages connected Emlaghfad church with the castle and with the Franciscan Abbey.