An archdeacon is a senior clergy position in the Church of the East, Chaldean Catholic Church, Syriac Orthodox Church, Anglican Communion, St Thomas Christians, Eastern Orthodox churches and some other Christian denominations, above that of most clergy and below a bishop. In the High Middle Ages it was the most senior diocesan position below a bishop in the Catholic Church. An archdeacon is often responsible for administration within an archdeaconry, which is the principal subdivision of the diocese. The Oxford Dictionary of the Christian Church has defined an archdeacon as "A cleric having a defined administrative authority delegated to him by the bishop in the whole or part of the diocese." The office has often been described metaphorically as oculus episcopi, the "bishop's eye".