DIACONICON, in the Greek Church, the name given to a chamber on the south side of the central apse, where the sacred utensils, vessels, etc., of the church were kept. In the reign of Justin II. (565-574), owing to a change in the liturgy, the diaconicon was located in an apse at the east end of the south aisle; a similar apse at the east end of the north aisle was used as the prothesis (q.v.)—the place where the elements of the Com munion were prepared. In the churches in central Syria, of slightly earlier date, there is only one apse and the diaconicon is rec tangular. (T. F. H.) DIADOCHI, i.e., "Successor" (Gr. btaoxecrOat), the name given to the Macedonian generals who fought for the empire of Alexander after his death in 323 B.c. The name includes Antig onus and his son Demetrius Poliorcetes, Antipater and his son Cassander, Seleucus, Ptolemy, Eumenes and Lysimachus. The kingdoms into which the Macedonian empire were divided under these rulers are knovvn as Hellenistic. The chief were Asia Minor and Syria under the Seleucid dynasty (q.v.), Egypt under the Ptolemies (q.v.), 'Macedonia under the successors of Antig onus Gonatas, Pergamum (q.v.) under the Attalid dynasty. Gradually these kingdoms were merged in the Roman empire. (See MACEDONIAN EMPIRE.) (X.)