sentences:  He was the third son of Bolesław IV of Warsaw and Barbara Olelkovna of Slutsk-Kapy, a Lithuanian princess, (granddaughter of Vladimir Olgerdovich).The premature death of his two older brothers during 1453-1454 left him as the eldest surviving son of his family.After the death of his father on 10 September 1454, Konrad III and his younger siblings were placed under the guardianship of their mother Barbara and Paweł Giżycki, Bishop of Płock.