Complex sentence: It is one of three principal structures atop the highest vantage point in the city and a series of stelae was set in front of it that described the military campaigns of Itzamnaaj B'alam II. Martin & Grube 2000, p.124.
Split into simpler sentences: It is one of three principal structures atop the highest vantage point in the city. In front of it was set a series of stelae describing the military campaigns of Itzamnaaj B'alam II. Martin & Grube 2000, p.124.