reposted from http://brigid-undertheoak.blogspot.com/
Sillan was born, probably a little before or about the middle of the sixth century, but the place does not appear to be known. It is said, he became a disciple to St. Comgall, the first Abbot of Bangor. Sillan was distinguished for his virtues and learning. On account of his erudition and proficiency in scriptural knowledge, he was chosen as professor and rector, over the monastic school. Hence, he enjoyed the title of Magister, or Master.
Beogna, who was Abbot of Bangor, died on the 22nd day of August, a.d. 605. In the Annals of Inisfallen, however, the rest of Beoguini is recorded, 601. St. Siollan was elevated, in succession, to the dignity of Abbot, as the third superior, over this renowned monastery. In the year 609, the burning of the monastery of Bennchoir, in Ulad, is recorded, in the Annals of Inisfallen; but, this happened, most probably, after the time of Sillan. This saint did not long survive his predecessor, in ruling over the monastery for, in about half a year after Beogna's death, according to our " Annals of the Four Masters," Sillan was called to bliss, after having faithfully discharged the duties of his stewardship, in this life. According to the Annals of Inisfallen, at a.d. 604, the death of a Sillain—probably intended for this saint—is placed. He departed on the 28th day of February, in the year
606, according to the Annals of the Four Masters. Again, the same day, but the year 609 is set down, in the Annals of Ulster, for his demise. The Annals of Clonmacnoise have the same date. The Annals of Tighernach have his death, at a.d. 610.
The Irish Martyrologists place the festival of St. Sillan, at this day. Thus we find, in his Festilogy, St. Oengus has an early notice of this holy superior. His name is inserted as Sillan, Abbot, Banchoir, in the Martyrology of Tallagh, at the same date. The Calendar of Cashel, and Marianus O'Gorman, at this day, commemorate him, as the Abbot of Bennchor and the comorban or successor of St. Comgall. He is noted as a Confessor, in the ancient Martyrology of the Cathedral Church of the Holy Trinity, Dublin, where his feast is inserted at the ii. of the Kalends of March—corresponding with the 28th of February. Again, in the Martyrology of Donegal, we find mentioned, as having a festival on this day, Siollan, Master, Abbot of Bennchair-Uladh, and successor of Comghall. In Scotland, likewise, this distinguished superior received his share of honour. The holy Abbot, Sillan, departed to Christ in Ireland, on the ii. of the March Kalends, or on the 28th of February, according to the Drummond Kalendar. His personal sanctity gained him the admiration and love of all his community; while his repute for learning has survived, although its manifestation may not now exist, in the shape of works attributed to him.
Troparion of St Sillan (Tone 7)
Under thy God-pleasing rule, O Father Sillan,
Bangor's monastery became a power-house of the true Faith.
As thou wast a bright beacon,
guiding men on their journey to God,
we beseech thee to be also a beacon for us,
bringing us safely into the way of salvation.
Kontakion of St Sillan (Tone 2)
Righteous Father Sillan, Road to our Saviour,
Crown of Bangor's saints and joy of all monastics,
we keep festival in thy honour, ever blessing thy name
and imploring thy prayers for us sinners.