Diego Gallego did not appear on the 1540 muster. Only because of the death of fellow expeditionary Juan Jiménez in the Tiguex province, do we know that Diego Gallego was present on the Expedition. There is a Pasajero record from 1521 in which a Diego Gallego accompanies the royal treasurer Alderete to New Spain along with two other expeditionaries, Rodrigo Simón and Lope Gallego. Because of these two expeditionaries, we suggest that this Diego is also an expeditionary. Also, many Gallegos are from Galicia which would match with Diego's birthplace.
pre 1530:
?Orozco y Berra in Dorantes de Carranza, Sumaría relación, 397 = Boyd-Bowman, Indice geobiográfico, II:7105 [w/Alderete, from Vigo:Pontevedra]
1530-1540:
?AHP, Legajo 9.142, Oficio 15, 1535 I [fol.609v: debt: Diego Gallego, potter, Leonor Cháves, his wife; vecinos of Triana; 28 May; doesn't know how to write];
?AHP, Legajo 9.143, Office 15, 1535 [Poder: Leonor de Chávez, vecina of Triana, wife of Diego Gallego, que al presente esta ausente de esta ciudad de Sevilla en las Indias, assigns her poder to Alonso Garrovero, her yerno (son-in-law), September 9, 1535 [Chávez does not know how to write]
?AGI, Pasajeros, L.2, E.4850 [April 3, 1538, son of Diego Gallego and Margarita González de Valdivieso, vecino of Doñavieja, to Nueva España]
1540-1550:
“Disposal of the Juan Jiménez Estate,” in Flint & Flint, Documents, Document 27 [March 1542, Gallego witness in Tiguex province]