He was engaged in warfare with the Bohemians and their Polish allies, when on 18 March 1438, he was chosen "King of the Romans" at Frankfurt, an honour which he does not appear to have sought.
Ia sibuk berperang dengan bangsa Bohemia dan sekutu Polandia mereka, ketika pada tanggal 18 Maret 1438, ia terpilih sebagai "Raja Romawi" di Frankfurt, suatu kehormatan yang kelihatannya tidak dicarinya.