Easton's Bible Dictionary (1897)
There are three kings designated by this name in Scripture. ) The father of Darius the Mede, mentioned in Dan. 9:1. This was probably the Cyaxares I. known by this name in profane history, the king of Media and the conqueror of Nineveh. C. 529). ) The son of Darius Hystaspes, the king named in the Book of Esther. C. 485). In the LXX. version of the Book of Esther the name Artaxerxes occurs for Ahasuerus. C. 486-465). He invaded Greece with an army, it is said, of more than 2,000,000 soldiers, only 5,000 of whom returned with him.
Leonidas, with his famous 300, arrested his progress at the Pass of Thermopylae, and then he was defeated disastrously by Themistocles at Salamis. It was after his return from this invasion that Esther was chosen as his queen.
Smith's Bible Dictionary (1863)
(lion-king), the name of one Median and two Persian kings mentioned in the Old Testament.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
AHASUE'RUS (probably lion king), the Hebrew form of Xerxes, the name, or perhaps only the title, of one Median and two Persian kings mentioned in the Old Testament. The father of Darius the Median, and the same with Astyages. Dan 9:1. Supposed to be the son and successor of Cyrus, probably Cambyses, who reigned seven years and five months from b. c. Ezr 4:6. The husband of Esther, undoubtedly the Xerxes of profane history. Esth 1:1.
The story of his acts of caprice and cruelty recorded in the book of Esther agrees exactly with what we otherwise know of his character, for once he scourged the sea and beheaded the engineers because a storm carried away their bridge, and was guilty of many other crimes. In the third year of his reign he called a council of his nobles, very likely for the purpose of arranging the invasion of Greece. The meeting lasted six months, and was followed by a munificent feast, on the seventh day of which he commanded his queen, Vashti, to show herself unto his drunken nobles.
This she properly refused to do, where upon he deposed her. Four years after, he married Esther. The interval is accounted for by supposing the war with Greece intervened. See Esther.
Hitchcock's Bible Names (1869)
prince; head; chief