Complex sentence: Zuism is a new Pagan religious movement based on the Sumerian religion, which is officially registered in Iceland where, in late 2015, it came to be adopted as a mass protest against a nationally mandated "parish tax" to support religions.
Split into simpler sentences: Zuism is a new Pagan religious movement based on the Sumerian religion, which is officially registered in Iceland. In late 2015 it came to be adopted as a protest against a nationally mandated "parish tax" to support religions.