Here is your short paragraph on Mahavrata:
This is an age-old village fertility festival. This occurs at the winter solstice to drive away impacts of the demons which might impede the return of the sun and as a result, retard plant growth.
This ancient popular festival of the villager was later turned into a religious festival by the Brahmans who took advantage of its immense popularity.
There are still a number of folk-elements remains such as the use of swings, in the belief that the higher one swung the higher the crops would grow. Races were run to increase the fertility of the soil, accompanied by the beating of the earth-drum made by digging a hole and covering it with hide.
The power in the eerie sounds made by it enabled the sacrificers ‘to conquer the earth’.
Ritual abuse was exchanged between a courtesan and a brahmacarin, a brahman and a sudra fought for a white round skin (a symbol of the sun); young girls danced holding water pitchers (kumbha), singing ‘this is honey’ (madhu), which is said to endow the sacrificers with might.
Sacral coition was also carried out under a covering. All this was ‘amalgamated’. With the artificial litany and saman engendered by the Agnicayana rite.