Cosmas of Prague
When he succeeded his father as duke, his coronation was celebrated with the first known rendition of "Hospodine pomiluj ny", the earliest known song in Czech. After his accession to the throne, he went at once to Regensburg to receive imperial confirmation. According to the contemporary chronicler Cosmas of Prague, this loyalty to the Holy Roman Empire did not prevent him from expelling all Germans from his lands, including his mother Judith, and the new anti-German policy continued to his death.