The kiss of peace is a traditional Christian greeting dating to early Christianity. The practice remains a part of the worship in traditional churches, including the Roman Catholic Church, Eastern Catholic Churches, Eastern Orthodox churches, Oriental Orthodox churches and some liturgical mainline Protestant denominations, where it is often called the kiss of peace, sign of peace, or simply peace or pax. It is practiced as a part of worship in many Anabaptist heritage groups including Old Order Mennonite, Old Order Amish, Old German Baptist Brethren, and Apostolic Christian.