4 Seasons chess is a medieval chess variant from the "Libro de los juegos" of Alphonso X "The Wise" of Spain. Invented in the 13th century, it is based on the medieval concept of the four seasons corresponding to the four humors, Spring to Sanguine, Summer to Choleric, Autumn to Melancholic, and Winter to Phlegmatic. From the translation (via St. Thomas guild[and he thru chessvariants.com):

"Here begins another chess that was made after the four seasons of the year, which the ancient wise men divined
There is another chess that the ancient wise men made after the four seasons of the year and it was organized in this way: The first season is spring which begins in the middle of March and goes through the middle of June. The second season is summer which begins in the middle of June and goes through the middle of September. The third season is autumn which begins in the middle of September and goes through the middle of December. The fourth season is winter which begins in the middle of December and goes through the middle of March. And these four seasons are divided like the four elements. Spring is air; summer is fire; autumn is earth; winter is water.
And because as we said above in the first season, spring, all things grow and men are refreshed and the trees and plants turn green the reason why air is its element is clearer than for any other season; therefore they made this season green. And the summer which is hotter and drier than the other seasons they made it like fire, which is of this nature. And therefore they made this season red for it element which also is. The autumn is dry and cold because its element is earth; it is more temperate than summer because it tends more toward cold than heat. The things that burn in summer, are born and refreshed in this season. And because its element is earth, its nature coldness and dryness therefore they made this season’s colour black. Winter they gave the element water which is cold and wet because in that season there are great cold, ice, snow, and rains. And because its element is water they made its colour white. And this similarity they made according to the four humours that grow in the body of man, like blood, which they gave to spring; and choler, to summer; and melancholy, to autumn; and phlegm to winter.

Of the humours which grow in each season
Of these four seasons we described above, the first is spring. And the blood grows in it more than in all the others. And in the summer, choler; in the autumn, melancholy; and in the winter, phlegm.
The seasons are divided in this manner: spring is temperate because it is between winter which is very cold and summer which is very hot. According to the ancient wise men, it tends more towards warmth than cold because it takes more from summer which is coming than winter which is passed. Summer is hot and dry because of the warmth from the previous spring and the warmth of the coming autumn. Autumn is temperate and tends more towards cold than warmth because it is between summer which is very hot and winter which is very cold, taking more from the coming season than the past. Winter, which comes between autumn and spring, is very cold because it takes coldness from the previous autumn and from the coming spring. And in this way the seasons all take from one another. And like the four seasons and the four humours they divided the pieces of this chess into four parts, each with its own colour as you heard above, which suits each season. "