Fr João de S Nicolau was the son of Francisco de Abreu Castelo Branco and Dona Severina Antonia de Mendonca. he was born in Vila de Moura in the Parish of Our Lady of Good Voyage ( Boa Viagem). He was based in Macau but returned to Goa on 14th September 1764. He was Rector of the Colegio do Populo de Goa in 1768 and occupied various other posts. He was elected Definitor 3rd time in October 1791 but could not take charge due to ill health. He died in Daugim on 30th June 1791 and was buried in the Convent of Grasa ( Grace) de Goa.