She was born at Fochard, near Dundalk, about the year 453, where her parents happened to be staying at the time; but Kildare was their usual place of residence, and there the holy virgin began her saintly career.

In her sixteenth year she received the white cloak and religious veil, which was then the distinctive garment of those who were specially dedicated to Christ, from the hands of St.Macaille, the Bishop of Usneach, in Westmeath.
Eight young maidens of noble birth took the veil with her.

Their first residence was at a place in the King's county, still called Brigidstown.
The fame of her sanctity now extended far and wide, and she was earnestly solicited from various parts of the country to found similar establishments.

Her first mission was to Munster, at the request of Erc, the holy Bishop of Slane, who had a singular respect for her virtue.
Soon after, she founded a house of her order in the plain of Cliach, near Limerick; but the people of Leinster at last became fearful of losing their treasure, and sent a deputation requesting her return, and offering land for the foundation of a large nunnery.

Thus was established, in 483, the famous Monastery of Kildare, or the Church of the Oak.
At the request of the saint, a bishop was appointed to take charge of this important work; and under the guidance of Conlaeth, who heretofore had been a humble anchorite, it soon became distinguished for its sanctity and usefulness.