The difficult navigation of the harbour gave security to the locals, as larger attacking ships could not enter. The sandbanks and narrow channels did not present much difficulty to the Dunkirk frigates or the local shallow draft cargo ships. Cromwell By the mid-1640s, the privateering community of Irish, Flemish and French based in Wexford had a fleet of 200 cargo ships and 21 frigates whose purpose was to attack English ships between Biscay and the Baltic. Within a few years this fleet had doubled. However, it could not last. In 1649, a parliamentary army under Oliver Cromwell landed in Dublin and after some months set out to conquer Wexford. An army of 7,000 foot soldiers and 2,000 cavalry camped north of the town and sent a detachment to capture Rosslare fort at the mouth of the harbour. This enabled Cromwell's fleet to enter the harbour unopposed. The army moved to south of the town and bombarded Wexford Castle. Initially, Cromwell issued a summons to surrender, offering lenient terms in the hope that he could secure Wexford intact and use it as winter quarters for his troops. The mayor, aldermen and many citizens of Wexford were prepared to surrender but the military commander played for time. Cromwell lost patience and talks broke down. The bombardment continued and after a week or so Cromwell's troops breached the defences when the commander of the castle surrendered. The castle guns were turned on the town and Cromwell's troops launched an immediate attack on the town's defenders. Irish troops made a stand in the market square, but they were quickly overwhelmed. Cromwell and his officers made no attempt to restrain their soldiers, who slaughtered the Wexford defenders and plundered the town. Hundreds of civilians were shot or drowned as they tried to escape the carnage by fleeing across the River Slaney. The Irish privateering fleet was finally broken up. Afterwards, Cromwell expressed no remorse for the massacre of civilians at Wexford in his subsequent report to Parliament. He regarded it as a further judgement upon the perpetrators of the Catholic uprising of 1641 and also upon the pirates who had operated out of Wexford harbour. His principal regret was that the town was so badly damaged during the sack that it was no longer suitable as winter quarters. Act of Union In 1764 the historian Amyas Griffith wrote that Wexford's chief export was corn (2