Medieval saints are often good at winning arguments. For your entertainment today, I bring you a story about St Fintán (or Munnu) of Taghmon. The story concerns the Easter controversy of the early seventh century, when many in Ireland felt that they should probably observe the same Easter as the rest of the world rather than the Easter using their traditional calculation. In 630 or so, a council at Mag Léne broke up without agreement on which Easter to use and a delegation was sent to Rome to find out what other people did. Traditionalists were unmoved by the information they received back but most in the south decided to follow practices in Rome. The debate rumbled on for nearly another century. But how do you decide whose calculations are right? Detailed discussion about the astronomical, theological and mathematical principles which lay behind the calculations? No. This is, according to Fintán’s hagiographer, how he tried to resolve the issue at ‘a great council of the Irish people’ in an argument with Laisrén of Leighlinn:

The next day, Fintán said to Laisrén in the presence of the people, ‘Now is the time for the council to end and each person to return home. Therefore, I suggest three things briefly to Laisrén. Two of our books should be placed in fire, a book of old ordo and of new ordo, so that we can see which book escapes from the fire. Or: two of our monks should be shut in one house and the house set on fire, so that we can see which of them is freed from the fire. Or we together – Laisrén and I – go to the sepulchre of a recently deceased just monk and we resurrect him, so that he can indicate to us which Easter is to be celebrated in Heaven’. To this Laisrén said, ‘I will not go in judgement against the Beast of God as, for the magnitude of your labours, if you said that Mons Marce should be switched for Campus Ailbe and Campus Ailbe for Mons Marce, God would do this for you’. Then Fintán said, ‘And so each should do what they believe and seems right to them’. [translated from W. Heist, Vita Sanctorum Hiberniae, Brussels 1965, p. 207].

Setting fire to books and people: not recommended ways to win an argument. But in this case, the threat of doing so was a good way to force a fudging of the issue at hand.