Complex sentence: Van Rensselaer, who has been described as having "... proved a lenient and benevolent landowner", was the patroon of the region at the time, and was a descendant of Kiliaen Van Rensselaer, the first patroon of the Manor of Rensselaerswyck.
Split into simpler sentences: Van Rensselaer, who was described as having "... proved a lenient and benevolent landowner". He was the patroon of the region at the time, and was a descendant of Kiliaen Van Rensselaer, the first patroon of the Manor of Rensselaerswyck.