A patron of the
Monastery of Guimarães, he first appears in the
curia regis of King
Ferdinand I of León in 1059, and with the title of count for the first time in 1070 when he appears confirming a donation made by King Garcia II. He married Goncina with whom he appears on 17 February 1071 making a donation to the
Monastery of Santo Antonino de Barbudo of some properties in Luivão (
Lage, Vila Verde), confirming as
Ego comes Nunus Menendiz et uxor mea comitissa domna Goncina ("I, Count Nuno Menéndez and my wife Countess dona Goncina"). On 18 February 1071 he fought in the
Battle of Pedroso, near the
Monastery of São Martinho de Tibães, and his defeat and death led the winning Garcia II to call himself King of Galicia and Portugal. The County of Portugal was then subsumed into the crowns of Galicia and León until regranted by King
Alfonso VI of León and Castile a quarter-century later. He owned properties in
Braga (
Nogueira, Santa Tecla, Dadim, Barros and
Gualtar) and
Porto (
Cerqueda) which were probably confiscated after his defeat and given later by King
Alfonso VI of León to his son-in-law
Sisnando Davides. Although the battle of Pedroso has been mistakenly dated in January of that year, as mentioned in the
Chronica Gothorum, this donation proves that the battle took place in February rather than in January. == Marriage and issue ==