English: The graphics were created on the basis of the Grand Duke Olgierd seal, imprinted by the Grand Duke himself. This seal was based on the historical sources.
Polski: Grafika została stworzona na podstawie pieczęci herbowej wielkiego księcia Olgierda, odciśniętej przez niego samego. Pieczęć ta została wykonana na podstawie źródeł historycznych.
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