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In page Livonia:

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In 1418, the Archbishop of Riga, Johannes Ambundii, organised the five ecclesiastical states of the Holy Roman Empire in Medieval Livonia (Livonian Order, Courland, Ösel–Wiek, Dorpat and Riga) into the Livonian Confederation.[1][2] A diet or Landtag was formed in 1419. The city of Walk was chosen as the site of the diet.[citation needed]