when his son bolesław succeeded him, poland remained an ally of the empire in the campaigns against the polabian lutici tribes. emperor otto ii, father of otto iii, died at age 28 in 983 and his widow theophanu and grandmother reigned for the child-king otto iii. in 996 otto iii was crowned as holy roman emperor at rome. by the time of the congress at gniezno in 1000 ad, he was 20 years old.