Siege of Bartenstein was a medieval siege laid upon the castle of Bartenstein (now Bartoszyce in Poland) by the Prussians during the Great Prussian Uprising. Bartenstein and Rößel were the two major Teutonic strongholds in Barta, one of the Prussian lands. The castle endured years of siege until 1264 and was one of the last ones to fall into the hands of Prussians. Other castles at Wistotempil, Schippenbeil, and Kreuzburg felt sometime in 1263. The castles presented a definite threat to the Bartians and Warmians, who had to keep their armies at home and could not participate in wider uprising.