This constellation was formed by the Dutch theologian Petrus Plancius and first appeared on his celestial globe of 1612. The German astronomer Jacob Bartsch, who was keen to find Biblical references for all constellations, said in his book Usus Astronomicus Planisphaerii Stellati of 1624 that it represented the cockerel that crowed after Peter had denied Jesus thrice. Whether this was actually Plancius’s intention we cannot tell, for Plancius left no surviving records. Bartsch did not even know that Plancius was the inventor. He first saw Gallus on a globe of 1621 made by his countryman Isaac Habrecht and mistakenly attributed it to him.

Gallus lay in the Milky Way, south of the celestial equator in the northern part of what is now Puppis. Although a number of astronomers adopted Gallus, it was not shown on the influential charts of Johann Bode.

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