After his father's death in 1194, Konrad was brought up by his mother, who acted as regent of Masovia. In 1199, he received Masovia and in 1205 the adjacent lands of Kuyavia as well. In 1205, he and his brother, Duke Leszek I the White of Sandomierz, had their greatest military victory at Battle of Zawichost against Prince Roman the Great of Galicia–Volhynia. The Ruthenian army was crushed and Roman was killed in battle. The Rurik princess Agafia of Rus became his wife.