Fionnlagh MacCailein or Finlay Colini (died 1419) was a medieval Scottish bishop. Both his early life and the details of his career as Bishop of Dunblane are not well known, however it is known that he held the latter bishopric between 1403 and his death in 1419. He was part of the circle of Robert Stewart, Duke of Albany, and was one of the many clerics from west and central Gaelic-speaking Scotland who benefited from the latter's patronage. He is said to have authorised the construction of the first bridge over the river Allan at Dunblane.
He held a bachelor's degree in canon law by December 13, 1400. On September 15, 1402, Pope Benedict XIII provided Fionnlagh to a canonry (with the expectation of a prebend) in the diocese of Dunkeld; the mandate of provision contains information much about Fionnlagh, informing us that he was a priest, confirming that he possessed a bachelors degree in canon law, while also stating that he was Archdeacon of Dunblane.
He was said in the papal document to have held the hospital of Uthrogle and "a certain perpetual office or benefice without cure in the secular collegiate church of Abernethy"; the latter, we know from another papal source, was the lectorship of Abernethy called "ferlinn", i.e. fer léighinn (literally "man of letters"), a position which existed at Abernethy collegiate church into the 16th century.
By this period he was the chaplain of Robert Stewart, Duke of Albany. The patronage of the Duke of Albany, who importantly was also Earl of Menteith, was crucial to Fionnlagh's whole career; Fionnlagh's bishop at Dunblane was Dúghall de Lorne, another Albany man. Albany indeed petitioned for benefices of Fionnlagh's behalf, and all of the benefices Fionnlagh held lay within Albany's influence.
Some time after the death of Bishop Dúghall (last attested 1398 × 1401), Fionnlagh was elected as Bishop of Dunblane; on September 10, 1403, Fionnlagh was provided to the bishopric by the Pope directly, the election being illegal due - so it was claimed - to earlier papal reservation of the see. His unattested consecration, which was probably performed at the papal see, had certainly occurred by April 28, 1404.
At that date he is found back in Scotland as a full bishop attending a church council at Linlithgow. His activities and whereabouts as Bishop of Dunblane are not well attested. In 1404 the Pope mandated Fionnlagh as well as Henry de Wardlaw, Bishop of St Andrews, and Robert de Cardeny, the Bishop of Dunkeld, to preach a crusade against the Turks. He was at Dunblane on November 29, 1406, witnessing a charter of the Duke of Albany; he is next found on July 18, 1408, at a church council of the church held at Perth, and then again on October 28 of that year witnessing another charter of the Duke of Albany.
In 1411 Bishop Fionnlagh and two others were authorised by the papacy to use the income from the vacant diocese of Argyll to repair Lismore Cathedral, the seat of that bishopric. He is mentioned in a papal mandate issued to John, Abbot of Balmerino on June 1, 1414; John was a papal nuncio and collector in Scotland, and the mandate ordered him to offer his oath of fealty to the papacy through Bishop Fionnlagh; it is of note that Abbot John had once served as Fionnlagh's proctor at the papal curia.
The resignation of the earldom of Ross by Euphemia II, Countess of Ross, to the Duke of Albany on June 12, 1415 (probably at Stirling) was witnessed by Bishop Fionnlagh. He is found again on March 17, 1416 at a general council of the church held at Perth.
He is last known to have been alive on March 25, 1419, but was dead by October 30 when a papal mandate ordered the translation of William Stephani, Bishop of Orkney, to the now vacant see of Dunblane. The chronicler Walter Bower, writing a few decades after Fionnlagh's death, claimed that Bishop Fionnlagh was responsible for the building of a bridge over the river Allan at Dunblane.