Clan Sinclair to St Briavels Castle, and in 1296 he swore fealty to Edward I of England. In 1303 the Battle of Roslin took place where Scots under Henry Sinclair of Rosslyn and the Clan Comyn defeated an English force. The Battle of Loudoun Hill took place in 1307 where Scots under Robert the Bruce, assisted by Henry Sinclair of Rosslyn again defeated the English. The family initially favoured John Balliol's claim to the throne but later it became paramount that they gave their loyalty to Robert the Bruce. The Battle of Bannockburn was fought in 1314, where the Clan Sinclair fought
Robert the Bruce he delivered his infant daughter Marjorie as a hostage, which he never did. When King Edward returned to England after his victory at the Battle of Falkirk, the Bruce's possessions were excepted from the Lordships and lands that Edward assigned to his followers. The reason for this is uncertain, though Fordun records Robert fighting for Edward, at Falkirk, under the command of Antony Bek, Bishop of Durham, Annandale and Carrick. This participation is contested as no Bruce appears on the Falkirk roll of nobles present in the English army, and two 19th Century antiquarians, Alexander Murison and George Chalmers, have