Cassiopeia is a constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 in the northern sky, named after the vain queen Cassiopeia

Cassiopeia (mythology)

Cassiopeia is the name of several figures in Greek mythology.-Wife of Cepheus:The Queen Cassiopeia, wife of king Cepheus of Æthiopia, was beautiful but also arrogant and vain; these latter two characteristics led to her downfall....

 in Greek mythology

Greek mythology

Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...

, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century

2nd century

The 2nd century is the period from 101 to 200 in accordance with the Julian calendar in the Christian/Common Era. It is considered part of the Classical era, epoch, or historical period...

 Greek astronomer Ptolemy

Ptolemy

Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

, and it remains one of the 88 modern constellations today. It is easily recognizable due to its distinctive 'W' shape, formed by five bright stars. It is bordered by Andromeda

Andromeda (constellation)

Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...

 to the south, Perseus

Perseus (constellation)

Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...

 to the southeast, and Cepheus

Cepheus (constellation)

Cepheus is a constellation in the northern sky. It is named after Cepheus, King of Aethiopia in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...

 to the north.