Medieval England had a currency based on the Carolingian French denominations of pounds, shillings and pence. Most coinage was minted as silver pennies.
1 pound (£) = 20 shillings (s) = 240 pennies (d)
1s = 12d
The mark, used as a unit of account, equalled two-thirds of a pound
1 mark = 13s 4d
It is difficult to make meaningful comparisons with modern prices, but at this time £5 was considered a reasonable annual salary for a clerk; those with an annual income of £40 were considered sufficiently wealthy that they ought to take up knighthood; and an annual income of £1,000 was considered sufficient to maintain the estate of an earl. In the late thirteenth century, England’s total money supply was perhaps not much more than £1 million. The crown’s ordinary annual income was £26,828 3s 9¼d, according to a somewhat spuriously precise Exchequer estimate of 1284.
Gascony is a region of south-west France centred on Bordeaux. From 1154 until 1450, the kings of England ruled Gascony as dukes of Aquitaine. Technically, Gascony was a lordship within the larger duchy of Aquitaine, but in practice the English referred to Gascony and Aquitaine interchangeably.