The numerous wars which have occurred over the centuries have created many MIAs. The list is long and includes most battles which have ever been fought by any nation. The usual problems of identification caused by rapid decomposition were exacerbated by the fact that it was common practice to loot the remains of the dead for any valuables e.g. personal items and clothing. This made the already difficult task of identification even harder. Thereafter the dead were routinely buried in mass graves and scant official records were retained. Notable examples include such medieval battles as Towton, the Hundred Years' War, The Battle of Alcácer Quibir where King Sebastian of Portugal disappeared, the later English Civil Wars, and Napoleonic Wars together with any battle taking place until around the middle of the 19th century. Starting around the time of the Crimean War, American Civil War, and Franco-Prussian War, it became more common to make formal efforts to identify individual soldiers. However, since there was no formal system of ID tags at the time, this could be difficult during the process of battlefield clearance. Even so, there had been a notable shift in perceptions e.g. where the remains of a soldier in Confederate uniform were recovered from, say, the Gettysburg battlefield, he would be interred in a single grave with a headstone which stated that he was an unknown Confederate soldier. This change in attitudes coincided with the Geneva Conventions, the first of which was signed in 1864. Although the First Geneva Convention did not specifically address the issue of MIAs, the reasoning behind it (which specified the humane treatment of wounded enemy soldiers) was influential.