Visvaldis' feudal charter is the oldest such document surviving in Latvia, and in this charter Visvaldis is called "the king of Jersika" ("Vissewalde, rex de Gercike", in another document also "Wiscewolodus rex de Berzika").
Visvaldis' feudale charter er det ældste dokument af slagsen der stadig eksisterer i Letland, og i dette charter kaldes Visvaldis "Kongen af Jersika" ("Vissewalde, rex de Gercike"; i et andet dokument også "Wiscewolodus rex de Gercike").