Valacirca was created by Varda just before the Awakening of the Elves and as with Wilwarin, Soronúmë, Anarrima, and Menelmacar, she set them in the heavens as signs to come. Valacirca was meant to be a warning to Melkor of his eventual downfall.
It was also known as the Seven Stars, the Sickle and the Wain (by the Hobbits). Today it is comparable to a section of Ursa Major, known as the Big Dipper. Note: this was likely not Durin's Crow (also seven stars) which was likely the Northern Crown (Corona Borealis).