fabulous history, wife to Cepheus king of Ethiopia, and mother of Andromeda. She thought herself more beautiful than the Nereides, who desired Neptune to revenge the affront; so that he sent a sea monster into the country, which did much harm. To appease the god, her daughter Andromeda was exposed to the monster, but was rescued by Perseus; who obtained of Jupiter, that Cassiopeia might be placed after her death among the stars: hence the constellation of that name.

Astronomy, one of the constellations of the northern hemisphere, situated next to Cepheus. In 1572, there appeared a new star in this constellation, which at first surpassed in magnitude and brightness Jupiter himself; but it diminished by degrees, and at last disappeared, at the end of eighteen months. It alarmed all the astronomers of that age, many of whom wrote dissertations on it; among the rest Tycho Brahe, Kepler, Maurolycus, Lycetus, Gramineus, &c. Beza, the landgrave of Hesse, Rosa, &c. wrote to prove it a comet, and the same which appeared to the Magi at the birth of Jesus Christ, and that it came to declare his second coming; they were answered on this subject by Tycho. The stars in the constellation Cassiopeia, in Ptolemy's catalogue, are 13; in Hevelius's, 37; in Tycho's, 46; but in the Britannic catalogue Mr. Flamsteed makes them 55.

Cassius, in antiquity, a plated or metallic helmet; different from the galea, which was of leather.