Szolnok Castle was an important military fort for many centuries due to its prime location at the confluence of the Tisza and Zagyva rivers, in the middle of the Great Hungarian Plain. The area was the crossroads of several trade routes, including salt and lumber, as well as being a key route for armies passing between Buda and Translyvania. Against the advancing Ottoman forces in the 16th century, Szolnok and Eger were the only two forts protecting the heart of Hungary and Upper Hungary.