N.N. Alfonso de Léon

Fernão Mendes de Bragança "The old man", called by some genealogists Fernão Mendes de Antas (1020 —?) was a rich man and nobleman from the Portucalense county, and supposed ancestor of the Antas family.

He married a bastard daughter of D. Afonso VI of Castile from whom he had:

1. Fernandes Antas (1070 -?) married to Sancha Viegas de Baião (1080 -?) daughter of Egas Gosendes de Baião (1030 -?) and Unisco Viegas (1057 -?)
2. Afonso Fernandes Alão (c. 1070 - ?)

https://pt.wikipedia.org/wiki/Fernão_Mendes_de_Bragança_I