IRENAEUS, one of the Fathers of the Church; was bishop of Lyons, and suffered martyrdom about 202; had been a disciple of Polycarp; wrote against the Gnostics in a work in Greek, which all to a few fragments in Latin is lost.

IRE`NE, the daughter of Zeus and Themis, the Greek goddess of peace; she was an object of worship both in Athens and Rome, is represented as holding in her left arm a cornucopia, and in her right hand an olive branch.

IRENE, empress of Constantinople, born in Athens, a poor orphan girl, famous for her beauty, her talents, and her crimes; was banished to Lesbos, where she maintained herself by spinning; has been canonised by the Greek Church for her zeal in image worship (752-803).

IRETON, HENRY, born at Altenborough, Notts; graduated at Cambridge 1629, and studied law; on outbreak of Civil War he joined the Parliamentarian party, and marrying Cromwell’s daughter acquired great influence; took a leading part in the prosecution of the king, was one of his judges, and signed the warrant for his execution; kept by Cromwell in Ireland in 1650, he proved a stern deputy, and died of the plague before Limerick; he was a man of great vigour of character, whose zeal for justice made him almost cruel (1611-1651).

IRIDIUM, a metallic elementary body of rare occurrence, and found in the ores of platinum.

IRIS, the daughter of Thaumus (i. e. wonder) and of the ocean nymph Electra (i. e. splendour); was the goddess of the rainbow, and as such the messenger of the gods, particularly of Zeus and Hera, the appearance of the rainbow being regarded as a sign that communications of good omen were passing between heaven and earth, as it was to Noah that they would continue to be kept up; she is represented as dressed in a long wide tunic, over which hangs a light upper garment, and with golden wings on her shoulders.

IRKUTSK (421), a central Siberian province, separated from China by the Sayan Mountains; it has Lake Baikal on the E., Yenisei and Yakutsk on the W. and N.; a rich pastoral country, watered by the navigable rivers Angara and the Lena, agriculture, cattle rearing are prosperous industries; there are gold, iron, and salt mines; one-third of the population are forced colonists; the capital, Irkutsk (45), is the seat of government for Eastern Siberia, an ecclesiastical centre, and the chief emporium of commerce; it is the finest city in Siberia.

IRMIN, a Teutonic tribal deity; was honoured by wooden pillars with his image on the top, greatly reverenced by the people; the constellation “The Plough” was known as “Irmin’s Chariot.”

IRON AGE, the last of the three stages, stone, bronze, iron, which mark the prehistoric development of most now civilised peoples; these, of course, occurred at different periods, and were of different duration in different cases; they are named from the material employed in making cutting instruments and weapons; the forms of instruments are freer than in the bronze period, and rectilineal gives places to free curvilineal decoration; this age is marked, too, by the introduction of writing and the beginning of literary and historic records.  See AGES.