Emperor John V sought financial assistance from the West to help him with the Turkish threat in 1369 AD, but was arrested for failing to pay his debts to Venice. John was forced four years later to make Byzantium a vassal state and to pay homage and provide military support to the Turkish sultan. This agreement ended in 1421 AD when Sultan Murad II withdrew all privileges granted to the Byzantines during the reign of Emperor John V; Murad decided to capture Constantinople. His plan was carried out by his successor Mehmed II who carried out the final attack on 29 May 1453, releasing the Ottoman army on Constantinople. During this battle, Constantine XI was killed, thus putting an end to the existence of the Byzantine Empire. The fall of the Roman Empire in its entirety was inevitable and the reasons behind the fall are uncertain and endless. The following quote from historian Guy Halsall summarizes the true end of the Roman Empire