Many fiefs (fees) in the middle ages were for the use of land or for military service; but a fief was really simply service owed in exchange. Sometimes a peasant might owe "messenger service" and be obligated to don the lord's livery cloak and ride a message to another manor a specified number of times or at a specific time of the year. These service-fees were called serjeanty in England. Hence, sergeant-at-arms, etc. But here we read of a court jester who owed a very peculiar serjeanty in exchange for his land.
The Liber feodorum (Book of fees) for king Henry II informs us that:
Seriantia que quondam fuit Rollandi le Pettour in Hemingeston in comitatu Suff ’, pro qua debuit facere die natali Domini singulis annis coram domino rege unum saltum et siffletum et unum bumbulum, que alienata fuit per particulas subscriptas.
Which translates as:
"The serjeanty, which formerly was held by Roland the Farter in Hemingston in the county of Suffolk, for which he was obliged to perform every year on the birthday of our Lord before his master the king, one jump, and a whistle, and one fart, was alienated in accordance with these specific requirements."