An unconditional surrender is a surrender in which no guarantees are given to the surrendering party. In modern times, unconditional surrenders most often include guarantees provided by international law. Announcing that only unconditional surrender is acceptable puts psychological pressure on a weaker adversary, but may also prolong hostilities. Perhaps the most notable unconditional surrender was by the Axis powers in World War II.
After the Battle of the Trench, in which the Muslims tactically overcame their opponents while suffering very few casualties, efforts to defeat the Muslims failed, and Islam became influential in the region. As a consequence, the Muslim army besieged the neighbourhood of the Banu Qurayza tribe, leading to their unconditional surrender.
When Napoleon Bonaparte escaped from his enforced exile on the island of Elba, among other steps that the delegates of the European powers at the Congress of Vienna took was to issue a statement on 13 March 1815 to be an outlaw. The text includes the following paragraphs:
By thus breaking the convention which had established him in the island of Elba, Bonaparte destroys the only legal title on which his existence depended, and by appearing again in France, with projects of confusion and disorder, he has deprived himself of the protection of the law, and has manifested to the universe that there can be neither peace nor truce with him.
Consequently, as Napoleon was considered an outlaw when he surrendered to Captain Maitland of HMS Bellerophon at the end of the Hundred Days, he was not protected by military law or international law as a head of state, and so the British were under no legal obligation to either accept his surrender or to spare his life; however, they did so, exiling him to the remote South Atlantic island of Saint Helena.