Long witnessed deeds at Rye from 1402 to 1419, and his dealings with other townsmen included acting as a feoffee for Robert Onewyn in 1405 and making an agreement with John Salerne I in 1409, whereby he promised to sue on a bond for £15 12s.4d. and hand the sum recovered over to Salerne or else forfeit £100. From 1405 to 1421 he owned land in the neighbourhood of Rye at Udimore, Wilting, Brede and Wivelridge, on which as a Portsman he claimed exemption from taxation.
Like his presumed brother, Thomas, William had mercantile interests, which in his case included importing wine and exporting wool, sometimes, as in 1395, in his own ship the Mariebote of Winchelsea.
Next autumn (1405) Long’s ship, sent to join his friends the pirates of Dartmouth, led by John Hawley I, shared in the capture of a Spanish vessel sailing under safe conduct with a cargo of olive oil worth £210. As a consequence, on 2 Dec. the warden of the Ports was ordered to arrest Long and others of Rye and have them before the King’s Council within ten days; but Long could not be taken, so in January subpoenas in £200 were issued against him and Hawley’s other accomplices to restore the oil or appear to answer the Council on 9 Feb. Undeterred, Long then helped to capture a Prussian ship, for which offence his arrest was again ordered in March; and he later paid Rye 13s.4d., as its toll on the French prisoners he had taken in two other boats.
Two months after the beginning of the truce with Flanders, signed in June 1407, Long’s ship headed a squadron which captured two Flemish vessels laden with madder owned by merchants from Bruges. This particular art of piracy was to remain a bone of contention for four years, initially because there were delays in enforcing justice caused by the independent franchises of the Cinque Ports, whose warden, Sir Thomas Erpingham, was ordered in June 1408, on pain of £1,000, to execute a sentence of restitution, but without avail. Long had in fact gone to join the west country pirates in raids on Breton shipping, with the result that in September the warden and the bailiff of Rye were ordered to arrest him on this fresh charge and produce him in Chancery, and in October instructions went out for the seizure of his ship, the Marie, the confiscation of its cargo and the detention of its crew. Nevertheless, soon afterwards he took another Breton vessel carrying wine. It was not until 1411 that the Council, pressed by bitter necessity, insisted that the value of the goods captured from the Flemish merchants in 1407 (£215), together with £69 which the merchants and their agents had spent on their suit, should be awarded against Long and his accomplices, and orders be issued accordingly to the then warden, the prince of Wales.
In the meantime Long had not been idle. In October 1410, having sailed out in arms from the Camber, he allegedly shared with his new ally, Sir John Prendergest, in the capture of two Flemish salt ships which were brought into Rye a few weeks later. They had, however, chosen an unfortunate time for such exploits, for the King’s Council had just approved proposals to negotiate for the renewal of the truce with Flanders (due to expire in the following June), and the autumn shippings of English wool, sold as usual largely on credit, had recently reached the Netherlands. The duke of Burgundy now took advantage of Long’s and Prendergest’s depredations, as well as of rumours that a Flemish wine fleet had been detained at Southampton, to arrest all English merchants then in Flanders, together with their wool and debts, which were of far greater value than the Flemish losses. When the wine ships reached Flanders safely in January 1411, the duke released the merchants, but kept their property, from which some Flemings hoped to gain compensation for English piracies, if the truce were not renewed. A petition to Henry IV from the English merchants put the blame for their troubles squarely on Long and Prendergest. Although Thomas Walsingham, the chronicler of St. Albans, held that the English pirates were avenging injuries committed earlier by the Flemings and Normans, a memorandum on the proposed negotiations, submitted to the Council at this time, noted that the Flemish authorities had restrained their countrymen who had asked for letters of marque to secure redress, and that, despite their mounting losses, they were relying on the English King’s justice, Henry IV having personally promised a Burgundian envoy to enforce the truce strictly. The Council took the view, therefore, that not only should Long be deprived of his own letters of marque, which he had so noisily advertised (so causing ‘grant clamour’ in Flanders), but that restitution for previous piracies should be sternly exacted from the men of Rye.
Meanwhile Long, heedless of the diplomatic consequences of his actions, had recruited men in the Cinque Ports (more than 1,000 it was said) and in March 1411 set forth from the Camber with Prendergest, with whom he had been plotting their campaign at Appledore. Soon afterwards they captured two Flemish ships with cargoes of wine worth 1,000 marks and, following up this exploit with operations off the coast of Devon in which they cooperated with John Hawley II and other captains of Dartmouth, they not only preyed upon Flemish shipping, but also captured a Florentine carrack, owned by the Albertini, together with its valuable cargo of iron and wine from La Rochelle. The government dispatched commissions to the earl of Devon and others to arrest the pirates and seize their lands, ships and goods in the southwest, and, if not successful in detaining the miscreants, to make proclamation along the south coast warning them to appear before the King by 10 May and forbidding anyone to harbour or assist them thereafter. The pirates now turned eastwards, and in early April they captured no fewer than 14 more Flemish ships containing wine and salt valued at £3,000, as well as a Prussian vessel (which last, however, Long released for a ransom of part of its cargo). It was under these circumstances that the Anglo-Flemish conference for a renewal of the truce opened at Calais on 23 Apr.
Prendergest and long, their ships stuffed with plunder, put into the Camber the following day, and proceeded to exchange their captured wine for bread, meat and other victuals, which men from Rye and elsewhere in the neighbourhood hastened to sell them. Some of the salt was stored in Long’s house at Rye before being sold. John Salerne I bought from Long 200 marks’ worth of salt, iron and wine, Sir William Etchingham stocked up his cellars, while the vicar of Lydd opened his house to lodge Long and Prendergest. The juries that later indicted the pirates showed no hesitation in naming all those who trafficked with them, only taking care to note that they were not at the time aware that they were abetting their felony or treason. The pirates had in fact the moral backing of the whole English coast, and even in west Sussex several respectable landowners, including the bishop of Chichester, were suspected of having bought the plundered wine.
The government was not, however, prepared to be lenient. On 3 May it issued an order to the prince of Wales as warden, to muster the posse comitatus of Kent and Sussex (and of Hampshire and Surrey too, if necessary) to seize Long and Prendergest and their ships and property and, if he could not, at least to proclaim that no one should buy from them, supply them with provisions or otherwise assist them, on pain of being held a traitor; and this order was proclaimed at Dover and Rye two days later. However, Long’s only response was to gather his men on the 7th and sail up the Rother to Smallhythe (six miles inland) where lay a ship, the Juliane, reputed to belong to Prince Henry himself, which he audaciously carried off.
Henry IV’s Council was now faced with a diplomatic crisis. A provisional agreement had been outlined at Calais for releasing English property in Flanders and renewing the truce. Nevertheless, as Henry’s ambassadors reported, the Flemings were so enraged at Long’s doings that they rejected English demands for the release as a condition of further discussions, and held out for a better guarantee for restitution of the plunder. On 5 May the Four Members of Flanders wrote to the King complaining of his failure, despite all promises, to redress previous breaches of the truce by the pirates from Rye, and in particular of Long’s seizure of the wine fleet on the eve of the conference; and six days later they recalled their envoys. Henry’s ambassadors and the council of the Staple at Calais both wrote the same day to impress on him the danger of the position: if the truce were not to be renewed before 15 June, all English property in Flanders would be lost beyond recovery unless redeemed by force of arms; and the wool merchants, not receiving the price of wool sold on credit, would be unable to pay the customs dues, or repay their English creditors, so occasioning a huge loss to the royal revenue and threatening ruin to the whole English economy. The King’s Council saw that only by acting with real severity would it convince the Flemings of its determination to fulfil its pledges. So, at a meeting on 11 or 12 May, it resolved to entrust the chancellor himself, Sir Thomas Beaufort, then admiral of England, with the task of repressing Long, and immediately borrowed 200 marks from two London merchants to enable him to start his preparations in all haste. This was a first instalment on £1,000 which Prince Henry himself drew in tallies from the Exchequer on 15 May, for the wages of soldiers and sailors for Beaufort’s expedition ‘ad capiendum Willelmum Long et alios rebelles supra mare’.
A few days later juries empanelled at Dover and Canterbury indicted Long and Prendergest for treason and felony, for conspiring to break the truce and renew the war, for usurping royal power by levying men without the King’s leave and for despoiling foreign ships that had relied on the truce. Before long the admiral’s fleet caught up with Long, who was persuaded (Walsingham says by fair promises of impunity) to disembark and ride to London; and on 13 June he was lodged in the Tower, ostensibly until the next Parliament should assemble. His arrest enabled the duke of Burgundy to ratify the long-desired renewal of the truce.
Prendergest had taken sanctuary at Westminster. After obtaining a general pardon on 12 Nov. and armed with a fresh batch of letters of marque, he was able within a year to set about sacking French villages and breaking the new truce with Flanders.
In 1419 and 1420 William Long and his kinsman, Thomas, presented chaplains to the chantry of St. Mary and St. Nicholas, Rye, as its alternate patrons.