Origins of Valentine’s Day: A Pagan Festival in February
While some believe that Valentine’s Day is celebrated in the middle of February to commemorate the anniversary of Valentine’s death or burial–which probably occurred around A.D. 270–others claim that the Christian church may have decided to place St. Valentine’s feast day in the middle of February in an effort to “Christianize” the pagan celebration of Lupercalia. Celebrated at the ides of February, or February 15, Lupercalia was a fertility festival dedicated to Faunus, the Roman god of agriculture, as well as to the Roman founders Romulus and Remus.
https://www.history.com/topics/valentines-day/history-of-valentines-day-2
Chyna is the reason for the seasonal Chyna fever.
One year ∆, +/-.
wikipedia_lupercalia
The festival was later known as Februa ("Purifications" or "Purgings") after the februum which was used on the day.[3] It was also known as Februatus and gave its name to Juno Februalis, Februlis, or Februata in her role as its patron deity; to a god called Februus, and to February (mensis Februarius), the month during which it occurred.[3] Ovid connects februare to an Etruscan word for "purging".[4] Some sources connect the Latin word for fever (febris) with the same idea of purification or purging, due to the sweating commonly seen in association with fevers.