Donal Cam O’Sullivan Beare and his clan begin their epic march to Ulster on December 31, 1602. O’Sullivan has supported Hugh O’Neill, Earl of Tyrone, in his fight against Elizabethan England‘s attempts to destroy Gaelic Ireland once and for all. The cause O’Neill and O’Sullivan fight for is probably doomed after O’Neill’s defeat in the Battle of Kinsale in 1601, but the fight goes on, nonetheless.

O’Sullivan Beare conceals 300 of the women, children and aged of his community in a stronghold on Dursey Island, but this position is attacked, and the defenders hanged. In what is later termed the Dursey Massacre, Philip O’Sullivan Beare, nephew of O’Sullivan Beare, writes that the women and children of the Dursey stronghold are massacred by the English, who tie them back-to-back, throw them from the cliffs, and shoot at them with muskets.

After the fall of Dursey and Dunboy, O’Sullivan Beare, Lord of Beara and Bantry, gathers his remaining followers and sets off northwards on December 31, 1602, on a 500-kilometre march with 1,000 of his remaining people. He hopes to meet Hugh O’Neill on the shores of Lough Neagh.

O’Sullivan Beare fights a long rearguard action northwards through Ireland, through Munster, Connacht and Ulster, during which the much larger English force and their Irish allies fight him all the way. The march is marked by the suffering of the fleeing and starving O’Sullivans as they seek food from an already decimated Irish countryside in winter. They face equally desperate people in this, often resulting in hostility, such as from the Mac Egans at Redwood Castle in County Tipperary and at Donohill in O’Dwyer’s country, where they raid the Earl of Ormonde‘s foodstore.

O’Sullivan Beare marches through Aughrim, where he raids villages for food and meets local resistance. He is barred entrance to Glinsk Castle and leads his refugees further north. On their arrival at Brian Oge O’Rourke‘s castle in Leitrim on January 4, 1603, after a fortnight’s hard marching and fighting, only 35 of the original 1,000 remain. Many had died in battles or from exposure and hunger, and others had taken shelter or fled along the route. O’Sullivan Beare had marched over 500 kilometres, crossed the River Shannon in the dark of a midwinter night, having taken just two days to make a boat of skin and hazel rods to carry 28 at a time the half-kilometre across the river, fought battles and constant skirmishes, and lost almost all of his people during the hardships of the journey.

In Leitrim, O’Sullivan Beare seeks to join with other northern chiefs to fight the English, and organises a force to this end, but resistance ends when Hugh O’Neill, 2nd Earl of Tyrone signs the Treaty of Mellifont. O’Sullivan Beare, like other members of the Gaelic nobility of Ireland who flees and seeks exile, making his escape to Spain by ship. O’Sullivan Beare settles in Spain and continues to plead with the Spanish government to send another invasion force to Ireland. King Phillip III gives him a knighthood, pension, and the title Earl of Bearhaven, but never that which he desires most, another chance to free his homeland.

Many generations of O’Sullivan Beare’s family later achieve prominence in Spain. In 1618, Donal Cam O’Sullivan Beare is killed in Madrid by John Bathe, an Anglo-Irishman, but the legend of “O’Sullivan’s March” lives on.

The Beara-Breifne Way long-distance walking trail follows closely the line of the historical march.