Milton in Paradise Regained refers to "cold Septentrion blasts." The north wind, he means. In both English and Spanish, "septentrion" is "the north."
The Latin root of the word means "the seven plow oxen."
You might easily guess that the "seven plow oxen" are the seven stars of the Big Dipper, the most prominent constellation of the northern sky. By the time of Chaucer and Dante the term "septentrion" was applied not only to the constellation, but also to the north itself. You'll see the word on medieval maps.
The Romans imagined the seven oxen moving around a threshing floor, in keeping with the way the constellation turns on the fixed pole. The official name, of course, is Ursa Major, the Great Bear, but here in Ireland the constellation is commonly known as the Plow, and so it is appropriate enough to imagine oxen in the sky.