The diplomatic strategy of the Confederacy was based upon a faulty assumption. Government officials assumed that Southern cotton was so vital to European economies, especially the British, that active support would ensue. That support never arrived, despite a tendency of both Britain and France to imply they were about to side with the South. Economic realities worked to the Confederacy's disadvantage. Much of the bumper cotton crop of 1860 had ended up in European warehouses. This oversupply sharply reduced the demand for later cotton crops. And, as the North tightened its blockade of Southern ports, European textile manufacturers turned to new sources of supply in India and Egypt. Shortly after the outbreak of hostilities at Fort Sumter, President Jefferson Davis offered letters of marque to Southern ship owners, encouraging them to prey on Northern commerce. Lincoln countered by declaring a blockade of Southern ports. Britain responded properly under international law by declaring her neutrality. Both North and South were disappointed by the British position; each hoped to gain active support. In the end, this hurt the South more than the North. The most serious threats to Anglo-Union relations occurred in the Trent Affair of 1861 and the damage cause by the Alabama.