From Halopedia, the Halo wiki
Captain Iglesias was a UNSC naval officer who commanded the UNSC Dusk.
He commanded the prowler UNSC Dusk in 2552. Due to being wounded in action, he was undergoing six months of radiation rehab on Earth at the time of the Battle of Earth. His position was assumed by his capable first officer, Commander Richard Lash, who took the Dusk to Installation 05, and later, Onyx.
Iglesias was described as a capable man who had great confidence in his crew. Due to his injuries, he likely did not partake in the rest of the Human-Covenant War.
"Iglesias" means "church" in Spanish.