 Apart from the desire to maintain in existence historical and prestigious sees like Nicaea, this practice was most likely the result of their proximity to the seat of the Patriarchate in Constantinople, which allowed their bishops to both administer their dioceses and play an active role in the central administration of the Church.This practice became formalized in the 18th century, when the bishops of the dioceses closest to Constantinople (i.e.Bithynia and Eastern Thrace), who typically resided in the Ottoman capital and were members of the patriarchate's permanent synod, were elevated to "Elder" (γέροντες) metropolitans and formed a group with the power to check and counsel the Patriarchs.