Although it is not absolutely certain, Cristóbal Caballero was probably born in Zamora in the modern province of Zamora to Alonso Caballero and Isabel González. He most likely came to New Spain with don Pedro de Alvarado in 1538 and shortly after joined the Expedition along with Pedro's brother Jorge. Cristóbal was present at the 1540 muster as an unassigned horseman. There is one documentary record of a Cristóbal Caballero living in Acececa (Mexico) as its corregidor before 1565.
?AGI, Pasajeros, L.2, E.5515 = Boyd-Bowman, Indice geobiográfico, II:12717 [Cristóbal Caballero, son of Alonso Caballero and Isabel González, vecino of Zamora, October 17, 1538, came to New Spain with Pedro de Alvarado (we like the Alvarado connection and this is the only Cristóbal Caballero in Boyd-Bowman)]
1540, Feb: Muster in Flint & Flint, Documents, Document 12 [2 horses, several breastplates, helmet, beaver, native arms]
?AGI, Contaduría, 667A [lo que recibio de tributos de los pueblos que estaban en la real corona, 1565: a Juan de Busto pays 87 pesos on behalf of and a fiador for Cristóbal Caballero, corregidor que fue del pueblo de Açeçeca (near Pánuco on the coast]
?Chevalier, Land and Society [p.145:a Diego Caballero was rich refinery owner];
?Acuña, Relaciones Geográficas: México [Mexicaltzingo- corregidor-Gonzalo Gallegos; scribe-Francisco Sánchez Moreno; interpreter-Diego de Paz; governor-don Marcos de San Juan; fray Pedro Caballero; witnesses-Juan Téllez, Martín Osorio, Damián Gallegos, estantes]