In April 1543 Suleiman launched another campaign in Hungary, bringing back Bran and other forts so that much of Hungary was under Ottoman control. As part of a Franco-Ottoman alliance (see also: Franco-Hungarian alliance and Petar Keglević), French troops were supplied to the Ottomans in Hungary: a French artillery unit was dispatched in 1543–1544 and attached to the Ottoman Army. In August 1543, the Ottoman succeeded in the siege of Esztergom Other cities that were captured during this campaign are Siklós and Szeged in order to better protect Buda. However, continuous delay of the push toward the west, because of the siege of these fortresses, meant that the Ottomans could not launch any new offensive against Austria.