This magnificent church is the oldest archaeological monument from the Christian period in the city, dating back to the fourth century AD. It is one of the most famous landmarks in the city, and is frequented by Christians from all parts of the world because it was built on a site where Christians were martyred at the hands of pagans. This church has been renovated several times through the ages, the last of which was in the seventeenth century in the modern Portuguese style, but the church has remained inside in a beautiful Baroque style.