Mateo was born in Uclés, he is 30 years old.

Uclés is a heavily fortified town located near Toledo. Uclés is the seat and property of the Order of St. James (Orden de Santiago).

Mateo comes from a large family of successful wine merchant who gave all his sons basic education in the church school of Augustinians.

As a young man, he succumbed to the enticement of army recruits and the prospect of a quick profit, and was recruited into the army of the order of St. James. He served in the army for several years. Being able to read, write, and count, he worked his way up to the place of the supply sergeant.

He eventually participated in the siege of Gibraltar, where he met don Iñigo de Haro, but Mateo was seriously wounded in one foraging party raid. After a long fight with fevers, he finally miraculously recovered. He decided to make a pilgrimage to the grave of st. James to Santiago as a token of his gratitude that he survived.

Near the city, he was ambushed by highwaymen who were about to rob him, beat him and throw him into the ravine to die miserably. Luckily, the city guard guided by Jaime was nearby and managed to free Mateo and kill the robbers.

After completing his pilgrimage Mateo decided to stay in Compostella and joined the order of St. Augustine as a oblate or tertiary. He continued his service in the St. James army and befriended Jaime.

Jaime suggested Mateo as another travel companion to the ambassador don de Haro, and the envoy agreed. Many times, Mateos' military capability and education have been more than useful to our mission.