Well would you know the reason we sometimes pay bills quarterly goes back to the middle ages where 4 days are known as Quarter Days.
The perfect special day for my Craft Barn Alpha Challenge Page and the letter "Q".
The days are close to the Solstices and Equinoxes and are:-
Lady Day - 25th March
Midsummer's Day - 24th June
Michaelmas Day - 29th September
Christmas Day - 25th December
My dictionary definition even had this meaning in it so I highlighted it with glossy accents.