The paper aims to introduce into scholarly discourse a unique source of the late 1640s. This is an agreement (“ugovor") between the Russian government and the Safavid subject Murza Shakseitov on the production and supply of saltpeter to the Tsardom. The extraction of raw materials was planned to be carried out on the territory controlled by the vassal of Alexei Mikhailovich, the Endirey ruler Kazanalp ibn Sultan-Mahmud. The document is interesting both for its immediate content and the circumstances of its origin.