On February 25th, 1420, between Gjon Kastriot and the Republic of Ragusa was signed the agreement on trade exchanges. According to the document published by the albanologists Talloci Jiricek, Gjon Kastriot vowed to defend and to compensate any damage that may be caused ti the traders from Ragusa in its territories. The document also provided the customs duties for goods exchanged with the Republic of Ragusa. The trade agreement with Ragusa is a document that has come down to our days; it proves the existence of feudal principalities in lands of Arberia and state-building capabilities of Albanians of that period.