[3] He was thus a first cousin of another Gonçalo Vaz Guedes, father of the Portuguese humanist and rector of the University of Coimbra, Friar Diogo de Murça.

[5] He served in the military in Portuguese India and Ceylon together with his brother, Gonçalo Guedes.

During his tenure, he led several military operations in Colombo and in the Kingdom of Kotte, and was seriously wounded during these battles.

The last reference to him in the work of the 17th century Jesuit chronicler Fernão de Queiroz, entitled "Temporal and Spiritual Conquest of Ceylon",[6] mentions him as having fought in the defense of the fortress of Sri Jayawardenepura Kotte, in 1564, in the following terms: ''Captain Balthasar Guedes, anxious to avenge the wounds which he had received and not being able to stand on his legs, from an andor directed, encouraged [the others] and fought, the lack of feet being no obstacle, as he had hands".

[7] Neither he nor his brother Gonçalo married, nor did they leave any known descendants, so the paternal house was inherited by another brother, Gaspar de Sousa Guedes, married to the heiress of the majorat of Bulhão; with descendants in the majorats and later counts of Bertiandos, and in the Lemos family, Lords of Trofa.