Soper, whose father may have been a Winchester draper, had come to reside in Southampton and trade from that port by 1410. A competent and skilled administrator, he was soon given charge over the building up of a fleet of ships for Henry V. Although not officially appointed surveyor or clerk of the King’s ships until 1418, from four years previously he had been occupied at Burlesdon supervising the construction of a number of large vessels, and his official accounts date from 1415. On 29 Oct. 1414 he and his fellow customer of Southampton had received £80 for their services, and the very next day Soper was paid £125 for the safe-keeping of the Seynt Clare of Spain, a prize taken at sea, which was then being renovated under his supervision. In due course the Seynt Clare was reborn as the Holy Ghost, and in February following Soper received payments for having her decorated with heraldic devices and arms, thus completing works which cost the Exchequer nigh on £1,000. In this period the administration of the navy developed to wartime proportions, and storehouses and dockyards were built on the Hamble, with Soper being put in charge of operations. He became intricately involved in the organization of Henry V’s French expedition of 1415, and in April following, doubtless as reward, he was given an annuity of 20 marks, afterwards confirmed by Henry VI. Soper played a notable part in the greatest naval enterprise of the time, the scheme to build a ship of 1,400 tons’ estimated capacity—the Gracedieu—work on which, together with her two accompanying balingers, the Valentine and the Falcon, began in 1416 in a specially built dock at Southampton. She, the largest ship built in England before the 17th century, was to be described by the King’s brother Humphrey, duke of Gloucester, as ‘the fairest that ever men saugh’. Soper’s expenditure over a seven-year period in Henry V’s reign amounted to £7,500, some of which he received from the Exchequer in the form of assignments on the customs which he himself collected at Southampton.
Soper’s formal appointment as overseer of the King’s ships in 1418 gave him a daily wage of 1s. His work sometimes took him across the Channel to Normandy, where he organized the building of royal works, and in December 1419 he was granted a lease on a house at Harfleur. On 3 Feb. 1420 he became ‘keeper and governor’ of the royal fleet at double his previous pay, £40 p.a., and this office was confirmed by Henry VI’s council which, however, placed him under the controlment of Nicholas Banaster. From 1420 on he had a general mandate to make inquiries when and where he liked regarding the King’s vessels and their gear, and was also engaged in positions of trust, such as the transportation, in January 1422, of 20,000 marks from London to Southampton and thence to the King in France. After Henry V’s death one of the first orders of the Council was to direct that the bulk of the navy should be sold by Soper and others, and the naval establishment was as a consequence drastically reduced. Soper spent 101 days of the first year of the new reign riding to various ports to negotiate these sales, which raised some £995. Of this, 1,000 marks went to the late King’s executors, but some of the surplus was allowed to Soper himself, who in 1430 petitioned for payment of debts incurred when building the Holy Ghost and Gabriel, and while selling the remnants of the fleet in 1423-4, as well as for other labours over the previous 15 years. Such pleas for the payment of costs and wages, some long outstanding, show that his job was not all profit, and the sale of royal vessels may have provided an opportunity for him to recoup his losses. His salary, though high, was paid irregularly throughout his term of office, and privileges such as licences to trade could hardly have afforded a recompense for all his outgoings.
In the meantime Soper had not neglected his own mercantile interests, and these evidently brought him considerable profits. From 1412, if not earlier, he had been importing wine from La Rochelle. Two years later he was accused of the piratical capture of cargoes from Castile; and his trade with Italy, Spain and France included shipments of cloth, corn, iron, resin, nails, oil and slates. He took advantage of several special licences granted by Henry V and Henry VI: the first, addressed to him as ‘our esquire’ in 1415, permitted the shipment of 130 sacks of wool to Pisa; another, in 1420, exonerated him from payment of customs on 419 pockets of wool; a third, in 1424, allowed him or his factor, David Savage, to trade in Spain; and a fourth, issued two years later, gave him the unrestricted right to import salmon and hides from Ireland. Not surprisingly, Soper himself owned ships which were used for his trading ventures: for instance, having acquired Valentine, one of the royal fleet, he sent it to Bordeaux in 1426 with grain, coal, fish and kerseys. His years as clerk of the King’s ships and customer at Southampton lent a certain arrogance to his dealings; on one occasion when the royal searcher required the Valentine’s master to show his licence for exporting 700 quarters of corn, ‘he wolde not [indeed] nede not, bote made saylle and went awaye’. But Soper’s more ambitious schemes did not always prove successful: in 1429 and 1430 he joined with two other Southampton merchants, Walter Fetplace and Peter James, in obtaining royal licences for their factors to trade in Spain, but when Soper’s agent, Savage, arrived at Bilbao in July 1432 on a barge laden with cloth and other merchandise worth £500, he was arrested and held for ransom, and the cargo was confiscated. Disheartened by this experience, Soper made no further attempt to establish regular trading links in the Iberian peninsula.
In the meantime, Soper had become increasingly active in local government, and his election to no fewer than 13 Parliaments is a reflection of his high standing in the community. Having previously been three times mayor of Southampton, between 1428 and 1437 he was made responsible for paying the fee farm to Queen Joan.
Soper’s own property in Southampton, by 1431 assessed at £15 a year, comprised his dwelling-place, a house and quay known as ‘Isabell vaute’, and the building where the customs were collected, all situated in English Street. He renovated the two towers on the Watergate at his own cost, subsequently, in 1433, receiving from the town a 100-year lease of the premises (paying only a rose as annual quit rent), and also obtaining leave to build a shop on two plots next to the town wall. The lease was extended six years later, only then he assigned it to John Ingoldesby, ‘pro consilio michi impenso’, at an annual rent of £1.
In August 1452 Soper arranged with the warden of the Friars Minor at Southampton for a daily mass to be said in their church, where he proposed to be buried, for the souls of his parents, his wives and himself; and he gave the Franciscans two houses which he had had built in their cemetery. At Soper’s home in Eling three years later, Thomas Chamberlain, one of his executors, bound himself to pay the mayor and corporation of Southampton £2 every year after the deaths of Soper and his wife for their attendance at the obit.