There are two possibilities for the parentage of Diego Fernández. Either he could have been Diego Fernández, son of Fernando Gundemáriz & his wife Muniadomna Ordóñez or, secondly, he could have been Diego Fernández, son of Fernando Flaínez & his wife Elvira Peláez. Discussion about the relative merits of each case appears to revolve around the description of his daughter Jimena as "nieta del rey don Alfonsso [indicating Alfonso VI King of Castile], filla del conte don Diago de Asturias" in the "Corónicas" Navarras (as well as in other narrative sources). Menéndez Pidal, in order to explain this family relationship, hypothesised that Diego´s [second] wife “Cristina” was the daughter of Fernando Gundemáriz and his supposed wife “Jimena, daughter of Alfonso V King of León”. This approach would be consistent with the second possible parentage noted above, but ... there appear to be several difficulties with the hypothesis. A more straightforward solution is the first possible parentage noted above, which would satisfactorily explain the family relationship with King Alfonso VI and does not require any speculation about the parentage of Diego´s second wife.
Conde. "Diaco Fernandiz comes" confirmed the charter dated 19 Jan [1026] under which "Stephanus presbiter" donated "ipsa corte" to the monastery of San Andrés, San Facundo and San Martín in Tolia, Zamora. “...Didacus Fredenandiz comes...” subscribed the charter dated 30 Dec 1028 under which Vermudo III King of León donated “villam...Cordario” to Santiago de Compostela. The 24 Jul 1046 charter of his daughter Oneca [Mayor] appears to indicate that her parents were both deceased at that date. 1
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