Question: When did a storm disperse the fleet led by the English king who trusted William de Longchamp?

Knowledge 1: William de Longchamp
Longchamp governed England while Richard was on the Third Crusade, but his authority was challenged by Richard's brother, John, who eventually succeeded in driving Longchamp from power and from England. Longchamp's relations with the other leading English nobles were also strained, which contributed to the demands for his exile. Soon after Longchamp's departure from England, Richard was captured on his journey back to England from the crusade and held for ransom by Henry VI, Holy Roman Emperor. Longchamp travelled to Germany to help negotiate Richard's release. Although Longchamp regained the office of Chancellor after Richard's return to England, he lost much of his former power. He aroused a great deal of hostility among his contemporaries during his career, but he retained Richard's trust and was employed by the king until the bishop's death in 1197. Longchamp wrote a treatise on the law, which remained well known throughout the later Middle Ages. [SEP] Knowledge 2: Normans
In April 1191 Richard the Lion-hearted left Messina with a large fleet in order to reach Acre. But a storm dispersed the fleet. After some searching, it was discovered that the boat carrying his sister and his fiancée Berengaria was anchored on the south coast of Cyprus, together with the wrecks of several other ships, including the treasure ship. Survivors of the wrecks had been taken prisoner by the island's despot Isaac Komnenos. On 1 May 1191, Richard's fleet arrived in the port of Limassol on Cyprus. He ordered Isaac to release the prisoners and the treasure. Isaac refused, so Richard landed his troops and took Limassol.
Knowledge 1: John, King of England
The political situation in England rapidly began to deteriorate. Longchamp refused to work with Puiset and became unpopular with the English nobility and clergy. John exploited this unpopularity to set himself up as an alternative ruler with his own royal court, complete with his own justiciar, chancellor and other royal posts, and was happy to be portrayed as an alternative regent, and possibly the next king. Armed conflict broke out between John and Longchamp, and by October 1191 Longchamp was isolated in the Tower of London with John in control of the city of London, thanks to promises John had made to the citizens in return for recognition as Richard's heir presumptive. At this point Walter of Coutances, the Archbishop of Rouen, returned to England, having been sent by Richard to restore order. John's position was undermined by Walter's relative popularity and by the news that Richard had married whilst in Cyprus, which presented the possibility that Richard would have legitimate children and heirs. [SEP] Knowledge 2: Normans
In April 1191 Richard the Lion-hearted left Messina with a large fleet in order to reach Acre. But a storm dispersed the fleet. After some searching, it was discovered that the boat carrying his sister and his fiancée Berengaria was anchored on the south coast of Cyprus, together with the wrecks of several other ships, including the treasure ship. Survivors of the wrecks had been taken prisoner by the island's despot Isaac Komnenos. On 1 May 1191, Richard's fleet arrived in the port of Limassol on Cyprus. He ordered Isaac to release the prisoners and the treasure. Isaac refused, so Richard landed his troops and took Limassol.
Knowledge 1: William de Longchamp
Longchamp governed England while Richard was on the Third Crusade, but his authority was challenged by Richard's brother, John, who eventually succeeded in driving Longchamp from power and from England. Longchamp's relations with the other leading English nobles were also strained, which contributed to the demands for his exile. Soon after Longchamp's departure from England, Richard was captured on his journey back to England from the crusade and held for ransom by Henry VI, Holy Roman Emperor. Longchamp travelled to Germany to help negotiate Richard's release. Although Longchamp regained the office of Chancellor after Richard's return to England, he lost much of his former power. He aroused a great deal of hostility among his contemporaries during his career, but he retained Richard's trust and was employed by the king until the bishop's death in 1197. Longchamp wrote a treatise on the law, which remained well known throughout the later Middle Ages. [SEP] Knowledge 2: Arab–Byzantine wars
After his victory in the civil war, Muawiyah launched a series of attacks against Byzantine holdings in Africa, Sicily and the East. By 670, the Muslim fleet had penetrated into the Sea of Marmara and stayed at Cyzicus during the winter. Four years later, a massive Muslim fleet reappeared in the Marmara and re-established a base at Cyzicus, from there they raided the Byzantine coasts almost at will. Finally in 676, Muawiyah sent an army to invest Constantinople from land as well, beginning the First Arab Siege of the city. Constantine IV (r. 661–685) however used a devastating new weapon that came to be known as "Greek fire", invented by a Christian refugee from Syria named Kallinikos of Heliopolis, to decisively defeat the attacking Umayyad navy in the Sea of Marmara, resulting in the lifting of the siege in 678. The returning Muslim fleet suffered further losses due to storms, while the army lost many men to the thematic armies who attacked them on their route back.Among those killed in the siege was Eyup, the standard bearer of Muhammed and the last of his companions; to Muslims today, his tomb is considered one of the holiest sites in Istanbul. The Byzantine victory over the invading Umayyads halted the Islamic expansion into Europe for almost thirty years.

Answer: 1191