During the winter of 1346–47 the English army shrank, possibly to as few as 5,000 men at some points. This was due to: many soldiers' terms of service expiring; a deliberate reduction by Edward for reasons of economy; an outbreak of dysentery in Neuville which caused major loss of life; and widespread desertion. Despite his reduced numbers, between mid-November and late February Edward made several attempts to breach the walls with trebuchets or cannon, or to take the town by assault, either from the land or seaward sides; all were unsuccessful. During the winter the French made great efforts to strengthen their naval resources. This included French and mercenary Italian galleys and French merchant ships, many adapted for military use. During March and April, more than of supplies were run into Calais without opposition. Philip attempted to take the field with his army in late April, but the French ability to assemble in a timely fashion had not improved since the autumn and by July it had still not fully mustered. Taxes proved ever more difficult to collect, with many towns using all available funds to reinforce their walls or equip their militia, and much of the nobility crippled by debt they had accumulated paying for the previous nine years of war. Several French nobles suggested to Edward that they may switch their allegiance. Inconclusive fighting occurred in April and May: the French tried and failed to cut the English supply route to Flanders, while the English tried and failed to capture Saint-Omer and Lille. In June the French attempted to secure their flank by launching a major offensive against the Flemings; this was defeated at Cassel.