Metropolitan Hilarion has just reposed as I’m writing this (may his memory be eternal!). It got me thinking that there may be questions as to just what a metropolitan is, how they’re differentiated from bishops and archbishops, etc., so here we go. A bishop is the highest degree of clergy in the church - beyond that there are elevations of status and honorifics, but as successors to the Apostles, bishops serve the continuity of the Church established by Christ, and are always monastics or widowers.
Metropolitan is a title that’s usually granted to senior bishops or archbishops especially those in charge of a large geographical jurisdiction (everywhere outside of Russia, i.e., ROCOR, is pretty darn large). In the Slavic tradition, a metropolitan outranks an archbishop (the opposite is true amongst the Greeks). Essentially, a Metropolitan is bishop in charge of a province or several provinces that may include a number of more minor sees which themselves are overseen by bishops and archbishops. Metropolitan Mark of Berlin and Germany has come to the US and will be commemorated until a new First Hierarch of ROCOR is elected by the synod of bishops.