She was granted abbatial powers by either St. Mél of Ardagh at Mág Tulach, or St. Mac Caill, Bishop of Cruachu Brig Ele (Croghan in County Offaly). After this, in 468 she followed St. Melrose to the Kingdom of Tethbae in the Irish interior.
In 480, she founded a monastery at Cill Dara on a pagan shrine to the Celtic goddess Brigid, with whom she shared her name. The site was under an oak tree at Drum Criadh.
Brigid founded two monastic institutions, one for both sex, and requested the assistance of St. Conláed (Conleth) to be the pastor. For centuries hereafter, Kildare was controlled by abbot-bishops and abbesses, with the Abbess of Kildare becoming the superior General of all Irish monasteries.
The Book of Armagh illuminates upon Brigid and Patrick's time in Ireland, saying:
Between St. Patrick and St. Brigid, the pillars of the Irish, there was so great a friendship of charity that they had but one heart and mind. Through him and through her, Christ performed many great works.
