1. Introduction
Parity indicates the equal treatment of interest groups under the law, in a historical context, specifically the treatment of different religious confessions in the states, countries, and communities. After beginnings in the Middle Ages – such as the coexistence of Christians, Muslims, and Jews in the Crusader States (ca. 1100 – ca. 1300) – parity became a current issue especially after the religious Reformation in the early 16th centur…