Part of Martin Gruneweg’s notes dedicated to Belz which was graciously given to the author by the outstanding Ukrainian historian Yaroslav Isaevych is analyzed. Martin Gruneweg (1562 – after 1615), who was born in Gdansk in family of German merchant, serve the Armenian merchants, became a member of the Order of Dominicans and became famous as the author of very interesting travel notes. Page of the Notes, which contains the references to Belz, is in the second part of Gruneweg’s description, where he talks about visit to cities and villages of Poland, Ukraine, Russia, the Balkan countries. A brief description of the city from 1582 is considered in the context of other written and cartographic sources and the results of archaeological studying of Belz. Through information from the Notes data on urban fortifications, authenticity of which is well consistent with written sources older and later than Gruneweg’s description is obtained. It was confirmed that connection between different parts of the city, separated by water flows and swamps, was maintained by wooden dams and platforms, mentioned by Gruneweg and evidenced by results of archaeological researches. This feature of communications was also characteristic for neighboring city of Cherven. On the basis of Gruneweg's reports, date of the first mention of town-hall in Belz, which existed more than a century earlier, was revised. Settlements, listed in the context of the report about Belz, visited by Gruneweg during his travel allow us to partially reconstruct the route of his arrival to Belz, and further way to Lviv. It was established that direction of roads from the northwest from Lublin through Krasnostav, Tishivtsi to Belz and from there through Kulychkiv, Mosty, Kulykiv, Zashkov to Lviv almost did not change from Early Middle Ages till now. Gruneweg's notes about the Częstochowa icon confirm constant historical tradition, which relates one of the main relics of Poland precisely with Belz. Other messages, which also show importance of retrospective analysis of late medieval sources for the studying of Early Medieval cities, are interesting too. Key words: Martin Gruneweg, Belz, written and archaeological sources, planning structure, retrospective analysis.