Caviar sturgeon from the Sea of Azov began reaching the tables of aristocratic and noble Byzantine Greeks in the 10th century, after the commencement of large-scale trading between the Byzantine Empire and Kievan Rus'. The main types of caviar are Beluga, Sterlet, Kaluga hybrid, American osetra, Ossetra, Siberian sturgeon and Sevruga. The rarest and costliest is from beluga sturgeon that swim in the Caspian Sea, which is bordered by Iran, Kazakhstan, Russia, Turkmenistan, and Azerbaijan. Wild caviar production was suspended in Russia between 2008 and 2011 to allow wild stocks to replenish. Azerbaijan and Iran also allow the fishing of sturgeon
Types of membership of Opus Dei for the contributions that they may have made to Opus Dei during their time in the organisation, this applies to all categories of membership. When, however, someone leaves the prelature unlawfully (i.e. without the permission of the Prelate) he or she commits mortal sin. Nevertheless, the Congregation for Bishops states: "The laity incorporated in the Prelature Opus Dei continue to be faithful of the dioceses in which they have their domicile or quasidomicile and are, therefore, under the jurisdiction of the diocesan bishop in what the law lays down for all the ordinary faithful". Types of membership of Opus Dei