¬_¬ knowledge?
el cid was the champion of castile and leon, but when the two-kings (brothers, and kings of castille and leon) he was "friend" of sancho, who got assassinated by his brother alfonso mainlly because alfonso was jealous that "el cid" was so famous, and after many problems with alfonso, el cid got "excomulgated" (idk the name in english, alfonso kicked him out of castille) , then he fought with any1 who could pay him, till he got his own army and became "sir" of many muslim reings and took valencia (he died bcs of an arrow after-battle there, but they just made his dead body ride the horse because he died at home and soldiers didnt knew he was dead, and every1 followed him and won a battle -_-).
And he was always christian, he only "worked" for muslims. In fact, in valencia a moorish guy killed one of his friends, and he sieged it for 19months, and with him the city became christian.
He was a 2meter man who could use a two-handed sword with one hand, who wants to fight him in those times which every1 was 1.5m?
In fact he's spanish national hero probably, altho we have many to take

.
This is very short of course, you can read it fully on the

ing very long book "cantar del mio cid"