One source of funds for the king’s treasury in the Middle Ages was a fee or tax on landholdings across the nation. Most often this was levied as an amount per knight’s fee, for example two marks or twenty shillings per knight’s fee. However, the quantum of land represented by a knight’s fee was notoriously variable. A knight’s fee was the service (read = fee) owed to the king in respect of land granted. Further complicating matters, there was no fixed relationship between income earned from a parcel of land and the fee owed to the king.
Early scutages were commonly charged per knight’s fee. On at least one occasion, however, the king decided to charge his tenants-in-chief according to the quantity of arable land held, measured by carucates. In 1220, the king taxed each carucate held. This had the effect of taxing larger manors a greater amount, such as Eustace de Watford, who held one knight's fee, might have paid 20 shillings in recent years, now paid more than double that amount. On the other hand, a smaller parish such as Cold Ashby, also one knight's fee, now paid only 16 shillings.
Carucates held in Guilsborough parishes in 1220 were as follows, largest to smallest:
Watford 21 (before transfer of part of the parish to Long Buckby)
Guilsborough 11 1/6 (without other small parishes such as Nortoft)
Long Buckby 11
Cold Ashby 8
West Haddon 7 1/3
Lilbourne & Clay Coton 6 ¾
Thornby 6 2/3
Cotes Goldington 4
Nortoft 2 2/3
The measure of carucates (or hides), while more indicative of the quantum of land held than a knight’s fee, is not consistent in terms of acres. One carucate was a measure of arable land, which excluded meadow, pasture and waste or unusable land, such as forests, marshes, or lakes. Even then, the measure in acres of one carucate was not the same across various parishes, because arable land in one parish might be more productive than arable land in another parish.
As defined today, the Hundred of Guilsborough contains about 40,000 acres. The above survey early in the time of King Henry III totals a fraction more than 152 ½ carucates. One carucate was four virgates (or yardlands) and for national taxation purposes at that time, each virgate might represent something like 25 or 40 acres, depending on who provided the metric. Those two metrics indicate Guilsborough Hundred contained about 15,000 or 25,000 arable acres, respectively. Therefore, all other land (meadow, pasture, and unusable land) totalled anything from 25,000 acres to 15,000 acres, or an additional 167% or 60%, respectively, over and above the arable acres.