Nothing is known about the parentage or ancestry of Rodrigo Muñoz de Guzmán.
The onomastic customs of that time dictate that, given his patronymic Muñoz, he must have been the son of a Munio (Muño) or Nuño.
On 20 February 1151, Gutierre Fernández de Castro with his wife Toda, and Rodrigo and his wife Mayor, Toda's sister, donated several properties that the sisters had inherited from their maternal grandparents, to the abbot of the monastery.
[1][3] Rodrigo Muñoz probably died shortly after 29 January 1186, the date when he last appears in medieval charters.
He married before 1150 Mayor Díaz, daughter of Diego Sánchez, who died in the Battle of Uclés, and of Enderquina Álvarez, daughter of Álvaro Díaz de Oca and his wife Teresa Ordóñez.