The Roman Catholic Diocese of Metz is a Diocese of the Latin Rite of the Roman Catholic church in France. In the Middle Ages it was in effect an independent state (prince-bishopric), part of the Holy Roman Empire, ruled by the prince-bishop who had the ex officio title of count. It was annexed to France by King Henry II in 1552; this was recognized by the Holy Roman Empire in the Peace of Westphalia of 1648. It then was part of the province of the Three Bishoprics. Since 1801 the Metz diocese is a public-law corporation of cult (établissement public du culte).