Canon O’Hanlon brings details of a reputed feast of Saint Sillen (Senilis, Siollán) at June 21. The original source is the Scottish hagiologist, Thomas Dempster (1579-1625). He was something of a hate figure for the Irish as he conveniently ignored the fact that in the early middle ages the term Scotia was applied to Ireland and thus he claimed the myriad of ‘Scottish saints’ found in the sources for his own country. The name Sillen, or more correctly Siollán, is shared by a number of Irish saints and it seems from what Canon O’Hanlon has to say that the Bollandists linked the June 21 commemoration to the saint of that name who was the teacher of Saint Columbanus. This Sillen or Sinell was associated with an island monastery in Lough Erne, his feast is remembered on November 12. There was also an abbot Siollán of Bangor who had a reputation as a master of the science of the computus, his feast is celebrated on February 28. Whether either of these has any connection to the saint claimed by Dempster as having a feast at June 21 is thus far from clear. But if nothing else Canon O’Hanlon’s entry below, from Volume VI of his Lives of the Irish Saints, illustrates some of the difficulties in understanding those lives: