From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

ARIUS ( 1Ma 12:7; 1Ma 12:20 ). A king of Sparta, grandson and successor of Cleomenes II. His reign lasted from b.c. 309 to b.c. 265, and he was contemporary with the high priest Onias I., the successor of Jaddua. Friendly letters were interchanged between Arius and Onias (probably about b.c. 300); and Jonathan Maccabeus refers to these communications in a letter which he sent by his ambassadors to Sparta ( c [Note: circa, about.] . b.c. 144), 1Ma 12:7 ff., 1Ma 12:19 ff. AV [Note: Authorized Version.] Darius in v. 7 is due to corrupt text.

International Standard Bible Encyclopedia [2]

a - rı̄´us , ā´ri - us ( Ἄρης , Árēs ): The reading of the Vulgate (Jerome's Latin Bible, 390-405 ad) adopted in the Revised Version (British and American) for the former reading Areus and Areios of Josephus. A king of Sparta (309-265 bc) who wrote the letter to Onias, the high priest, given in 1 Macc 12:7, 20-23. There were two Spartan kings named Arius, and three high priests named Onias. Chronology requires the letter mentioned to have been written by Arius I to Onias I, most probably in the interval between 309 and 300 bc. See Lacedaemonians .

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [3]

born toward the close of the third century, in Libya, according to others, in Alexandria. He wrote a theological work, Thalia, extracts from which are given in the writings of Athanasius. He died in 336. For his doctrines and their history, (See Arianism).