Complex sentence: The following year, Leszek II attacked the Duchy of Wrocław, who belonged to Henryk IV Probus; this was in response for the imprisonment of Leszek II's ally Przemysł II after a meeting in probably Barycz.
Split into simpler sentences: The following year, Leszek II attacked the Duchy of Wrocław, which belonged to Henryk IV Probus. This was in response for the imprisonment of Leszek II's ally Przemysł II after a meeting in probably Barycz.