St Fillan was an Irish missionary who came to Scotland from Ireland in the 7th Century to convert the Picts and the Scots to Christianity. Like most saints, not a lot of facts are known of St Fillan but there are plenty of stories that helped build his reputation.
St Fillan's name means wolf cub,or little wolf, and, according to legend, he was born in the Irish province of Ulster, with a stone in his mouth. Ashamed, his father threw him into a lake. St Fillan survived this terrible ordeal and was found by a Bishop called Ibar who adopted him and raised him as a Christian. St Fillan's mother was obviously overjoyed that her son had been saved and swiftly became a Christian as well.
St Fillan came to Scotland with his mother and moved around for a while before St Fillan settled in Auchtertyre near Tyndrum while his mother retired and passed away in 734AD on as island in Loch Lomond, Inch Cailleach ('The Nun's Isle').
St Fillan established a monastery in Auchtertyre and also founded the nearby site "the Holy Pool of St Fillan". It is worth mentioning that St Fillan is the patron saint of the mentally ill and that for a long time an act, that ironically seems fairly insane, was carried out in his name as late as the 19th century. Poor tortured souls were taken from all over the country, then dunked in the freezing St. Fillan's Pool before being bound and tied overnight in the chapel. Ignoring the subject's struggling and screaming, the monks then declared that if the ropes were loosened by morning then it was a sign from St Fillan that the patient had been cured of their insanity.
The stories of St Fillan's legend involve him once convincing a wolf who killed his oxen to plough his farm and also involve him tracking and killing an enormous boar, who had been terrorising the local villagers, with just a wooden club.
Robert the Bruce was such a believer and avid follower of the stories of St Fillan that he brought one of St Fillan's relics to the Battle of Bannockburn. St Fillan was said to spend hours in dark solitude writing his teachings with only the magical light that would emanate from his arm helping him. It was the bone of this arm that Robert the Bruce requested be with him at the Battle of Bannockburn.
The Abbot who was charged with looking after the arm bone, known as The Mayne, only brought the empty silver case as he didn’t want the relic to fall into English hands. The English army were far larger and superior, so chances of victory were extremely slim. On the eve of the battle, Robert the Bruce and his Abbot were praying for help to overcome their foes when a huge crack came from the empty silver case and The Mayne fell to the floor. News of this miracle quickly spread through the Scots forces, who against all the odds won the Battle of Bannockburn, liberating Scotland from foreign rule.
To say thank you to St Fillan, Robert the Bruce built the priory on the grounds of St Fillan's monastery. Not much remains of the ruins as many of the stones were used to build nearby farms but you can still see some of this archaeological site