Complex sentence: Manuel Risco, a 17th century Spanish historian, believed that Velasquita was the daughter of King Ramiro II of León, but Velasquita never appears in medieval charters as "filia Ranimiri regis", which would have been the custom at that time.
Split into simpler sentences: Manuel Risco, a 17th century Spanish historian, believed that Velasquita was the daughter of King Ramiro II of León. In fact, Velasquita never appears in medieval charters as "filia Ranimiri regis", which would have been the custom at that time.