Roman Catholic Diocese of Helena was formed to serve eastern Montana. The seat of the diocese is in the Cathedral of St. Helena in the state capital of Helena. It was completed in 1914. The bishops of the Diocese of Helena and their years of service: Roman Catholic Diocese of Helena The Diocese of Helena () is the Catholic diocese for western Montana with its cathedral located in Helena, the state capital. The diocese was erected from the year-old Vicarate of Montana on March 7, 1884, while Montana was still a territory. The diocese is a suffragan of the Archdiocese of Portland, which encompasses Oregon,
Coat of arms of Saint Helena shows the flag of England flying from the ship (when the shield was first introduced in 1874 the flag was a White Ensign). The motto is "Loyal and unshakable". The full coat of arms features, above the shield, a woman holding a cross and a flower. This represents Helena of Constantinople, also known as Saint Helena, after whom the island is named. The cross is shown as Helena is credited with finding the relics of the True Cross (cross upon which Jesus was crucified). The shield of the arms features on the flag of Saint Helena and the Governor's flag.