There was a traditional Greek saying which I remember reading, which translated as “Wheat harvest, wine harvest, war.”
The idea was that in an agrarian society warfare was often seasonal. In Greece the summer was too hot and the warfare was mostly in the winter and spring, starting just after the wine harvest.
In order to give the calendar for my fantasy setting an interesting and agrarian feel I intend to give each month a name based on what should be done within that month.
Thus there is the wine harvest month, but also a wheat sewing month, a livestock slaughtering month etc. I will note down a vague timeline of seasonal activities here and then decide which activity the month should be named after.
a useful link is here: http://www.penultimateharn.com/history/medievalfarmingyear.html
By Thys Fyre
I first encountered this poem on the blog above. It seems to be an anonymous English poem of the 14th or 15th century (Raymond Oliver, Poems without names: the English Lyric 1200-1500).
Januar: By thys fyre I warme my handys
Februar: And with my spade I delfe my landys
Marche: Here I sette my thynge to sprynge
Aprile: And here I here the fowlis synge
Maii: I am as lught as burdie in bowe
Junii: And I wede my corn well mow
Julii: With my sythe my mede I mowe
Auguste: And here I shere my corne full lowe
September: And with my flaylle I erne my brede
October: And here I sawe my whete so rede
November: At Martynesmasse I kylle my syne
December: And at Chritemasse I drynke redde wyne
another useful link is here : http://www.historylearningsite.co.uk/medieval_farming.htm
January: the hedge moon
Febuary: The manure moon
March: Birthing moon
April: plough moon
May: the harrow moon
June: Haymaking moon
July: Possibly the war moon.
August: Harvest moon
September: Threshing moon
October: Wine moon
November: Blood moon (slaughter of livestock)
December: The feasing moon
13th month: The hidden moon.
They use a lunar callendar of 13 months, each 28 days long, so that any illiterate can easily tell when it is in the year. This gives 364 days in the year.
Every generation, 22 years, there is an extra month, called the passing of the age. This month follows after the war month and helps to bring the callendar in line with the seasons of the lunar cycle. This is not a perfect correction, but the system has not been in place for long enough for it to cause any great problem.