SELEUCIDÆ, in Chronology. Era of the Seleucidae, or the Syro-Macedonian era, is a computation of time, commencing from the establishment of the Seleucidae, a race of Greek kings, who reigned as successors of Alexander the Great in Syria, as the Ptolemies did in Egypt. This era we find expressed in the books of the Maccabees, and on a great number of Greek medals struck by the cities of Syria, &c. The Rabbins call it the era of contracts, and the Arabs sherik dikarnain, that is, the "era of the two horns." According to the best accounts, the first year of this era falls in the year 312 B. C. being 12 years after Alexander's death.