Shaped by the particular economic and social conditions there, Magdeburg law took on various forms in the territory of present-day Poland. Local versions evolved, which were influenced by the municipal laws of their particular places of origin such as Breslau. The city of Breslau had been granted Magdeburg law some time before 1241. It was confirmed by Duke Heinrich III of Saxony in 1261 while the city was being rebuilt after the Mongol invasion. Afterward, Magdeburg lay judges issued an extensive legal memorandum on the constitution of the city and the courts. A copy of the Sachsenspiegel was sent to the people of Breslau as well. One of the earliest pieces of evidence of the transfer of Magdeburg law, this legal memorandum also reveals the close link between municipal laws and the Sachsenspiegel whenever law was transferred to Eastern Europe.