He was born circa 1576. His father was Baltasar Castaño de Sosa, and his mother was Inez Rodriguez de Montemayor.
He married Juliana Farias de Quintanilla, daughter of Juan de Farias and Maria Ana de Treviño Quintanilla.
Juana Gertrudis de Farias Garcia. She married Nicolas Flores de Abrego, son of Pedro Flores and Melchora Gutierrez de Abrego.
Tomas Garcia de Quintanilla. He married Isabel de Arredondo, daughter of Juan de Arredondo Aguero and Maria Francisca de Sosa. In 1684, he requested a dispensation to marry Maria de la Garza. They were married on 18 Oct 1684.
Lucas Garcia de Quintanilla. On 23 Feb 1667, he requested a dispensation to marry Josefa de Ayala Benavides in Monterrey.
Bernardo Garcia de Sosa. He married Maria de Saldivar Sosa, daughter of Vicente Saldivar y Reza and Maria de Sosa.
Nicolas Garcia. He married Nicolasa de Bracamonte.
Ana de Quintanilla. She married Bartolome Gonzalez in 1643.
Diego Garcia de Quintanilla, born 1611. He married Mariana Saldivar de Sosa, daughter of Vicente Saldivar y Reza and Maria de Sosa.
One of 12 original settlers of Monterrey. Registered a mine in Nuestra Señora de la Candelaria, in the sierra of Santiago, in 1598.