During 1258-1261 Bolesław was involved in a long and destructive war against Casimir I of Kuyavia and his ally Swantopolk II for the castellanie of Ladzka. To this end, the Greater Poland Duke allied with Wartislaw III, Duke of Pomerania-Demmin, Siemowit I of Masovia, Bolesław V the Chaste and Roman Danylovich, Prince of Navahradak. The war ended in a full victory and Ladzka returned to Greater Poland. The formal treaty was signed on 29 November 1259; however, Casimir I delayed in fulfilled the provisions of the agreement, which led in 1261 to a new military expedition.