Complex sentence: The Anti-Rent War (also known as the Helderberg War) was a tenants' revolt in upstate New York during the early 19th century, beginning with the death of Stephen Van Rensselaer III in 1839.
Split into simpler sentences: The Anti-Rent War (also known as the Helderberg War) was a tenants' revolt in upstate New York during the early 19th century. The incident began with the death of Stephen Van Rensselaer III in 1839.