Coma Berenices is a northern constellation and the only constellation named for a real person: Queen Berenice II of Egypt, the wife of Ptolemy III. Although it is relatively faint, under a dark sky many of its stars are visible as pretty streamers that look like strands of hair.
Berenice married Ptolemy, who was her cousin, in 246 B.C. As king, Ptolemy later went to war. The tale of Berenice says that to protect her husband, she promised to cut her beautiful hair and offer it to the gods if Ptolemy returned safely. He did, so she did. She placed her locks in a temple, dedicated either to the goddess Aphrodite, or to all the gods, depending on the version of the story. The hair soon disappeared. The court astronomer told the king that the locks had been taken by the gods and placed in the sky — streamers of stars near Leo, the lion. The story might be true, or might have been created — or at least embellished — to raise the king’s profile.
Coma Berenices didn’t become a constellation until 1536. And it didn’t enter wide-spread use until 1602, when it was included in an atlas published by Tycho Brahe.
It is best known for the Coma Cluster, a collection of thousands of galaxies centered within the constellation's borders.