text: Catholic response Since only 27 years had passed since the Fall of Constantinople, there was some fear that Rome would suffer the same fate. Plans were made for the Pope and the citizens to evacuate the city. Pope Sixtus IV repeated his 1471 call for a crusade. Several Italian city-states, Hungary and France responded positively. The Republic of Venice did not do so, as it had signed an expensive peace treaty with the Ottomans in 1479.
  In April 1481, Sixtus IV called for an Italian crusade to liberate the city, and Christian forces besieged Otranto in May. An army was raised by King Ferdinand I of Naples, to be led by his son Alfonso, Duke of Calabria. A contingent of troops was provided by King Matthias Corvinus of Hungary.
  Recapture
  Between August and September, King Ferdinand of Naples, with the help of his cousin Ferdinand the Catholic and the Kingdom of Sicily, attempted to recapture Otranto. The Christian forces besieged the city on 1 May 1481. Mehmed II was preparing for a new campaign on Italy but lost his life on 3 May. The succession issues prevented the Ottomans from sending reinforcements to Otranto. After negotiation with the Christian forces, the Ottomans surrendered in August, left Otranto in September 1481 and ended the 13-month occupation.
  Aftermath
  The number of citizens, which is said to have been nearly 20,000, had decreased to 8,000 by the end of the century.
  The Ottomans also briefly held Otranto once more after they conquered it in 1537.