Annales regni Francorum
According to Einhard, the writer of the "Royal Frankish Annals", following the final Frankish attack, Ljudevit fled from his seat in Sisak to the Serbs in 822 ("Siscia civitate relicta, ad Sorabos, quae natio magnam Dalmatiae partem obtinere dicitur, fugiendo se contulit."). In the contemporary "Vita Hludovici" that description of the Serbs is omitted. Ljudevit later killed the local Serbian župan who took him in and temporarily took over the rule in his župa.