Personal prelature is a canonical structure of the Catholic Church which comprises a prelate, clergy and laity who undertake specific pastoral activities. The first personal prelature is Opus Dei. Personal prelatures, similar to dioceses and military ordinariates, are under the governance of the Vatican's Congregation for Bishops. These three types of ecclesiastical structures are composed of lay people served by their own secular clergy and prelate. Unlike dioceses which cover territories, personal prelatures—like military ordinariates—take charge of persons as regards some objectives regardless of where they live.