Complex sentence: In 1014 Bolesław I sent his son Mieszko to Bohemia in order to form an alliance with duke Oldrich against Emperor Henry II. Bolesław I also refused to aid the Emperor militarily in his Italian expedition.
Split into simpler sentences: In 1014 Bolesław sent his son Mieszko to Bohemia in order to form an alliance with duke Oldrich against Emperor Henry. Bolesław also refused to aid the Emperor militarily in his Italian expedition.