A German adventurer who lived in Moscow Russia in the 16th century left rare historical evidence. His notes, found in archives only in the twentieth century, largely changed the previous ideas about the era of Ivan the Terrible. They are especially valuable in that the author was a direct participant in the events, served as the tsar's oprichnik, was in the thick of what was happening and even, according to him, personally met with the sovereign. Von Staden gives a description of the administrative structure of Muscovy of those times, its judicial system and troops. He gives a list of the most important "offices" - orders, vividly and figuratively reproduces the principles of their functioning, names the most influential princes and boyars at that time. It characterizes Moscow and the Kremlin in sufficient detail, and its description of the oprichny court, which lasted less than five years before it was completely burned down by the Crimean Khan in 1571, is truly unique.