Complex sentence: Orm Eriksson (ca 1476-1521) was a Norwegian nobleman living in Stavanger and the alleged leader of the tax revolt in Rogaland, which ended with his execution in 1521.
Split into simpler sentences: Orm Eriksson (ca 1476-1521) was a Norwegian nobleman living in Stavanger. He was probably the leader of the tax revolt in Rogaland, which ended with his execution in 1521.