Most iconography of months evolved from Medieval & early Renaissance art depicting in 12 scenes the rural activities that commonly took place in the months of the year. These early illustrations are important to the development of landscape painting.
A typical simple scheme might include:
January - Feasting
February - Sitting by a fire
March - Pruning trees, or digging
April - Planting, enjoying the country or picking flowers
May - Hawking, courtly love
June - Hay harvest
July - Wheat harvest
August - Wheat threshing
September - Harvesting Grapes or Orchard Fruit
October - Ploughing or sowing
November - Gathering acorns for pigs
December - Killing pigs, baking
But there were many variations, especially in major wine-growing areas, where more wine related scenes were included. Illustrations from further south, such as Italian cycles, often advance the agricultural scenes a month earlier than ones from the more northern Low countries or England.
