[1] She became the abbess on August 25, 1437, when she was ordained by bishop of Skálholt Gozewijn Comhaer.
Her parents were Finnur Gamlason, a lawyer in Ysta-Mói in Fljót, and his wife Valgerður Vilhjálmsdóttir.
Þóra was one of the eight nuns who Jón Vilhjálmsson Craxton ordained at Hólar on February 4, 1431.
Margrét Bjarnadóttir, widow of the lawyer Hrafn Guðmundsson, joined the convent and brought a substantial amount of wealth.
In addition, she gave land to the church of Hólar to lay to rest her husband, who was excommunicated when he died.