sentences:  The victory at the Belgrade (Nándorfehérvár) in 1456, where the fleet played a significant role in breaking through the Turkish river blockade to bring relief to the besieged city, showed its importance and signaled the beginning of a recognition of its significance.It also encouraged King Matthias to build a larger and better-equipped navy.Since they were manned by South Slavs, mainly Serbs and Croats, the two major ports of operations were Belgrade and Szabács (Šabac).