Judas Thaddeus Krusinski (1675-1755) was a Polish Jesuit who spent eighteen years in Persia, from 1707 to 1725, serving as Procurator-General of the Jesuit Mission from 1720 onwards. He learned Persian and became well acquainted with the country and its people. He acted as intermediary between the Papacy and the Safavid court and also acted as court translator. Crucially he resided in Isfahan in 1722 and was thereby witness to the siege of the city by Afghan tribesmen and its subsequent fall. Rudi Matthee is Munroe Professor of Middle East History, University of Delaware, USA. A leading scholar on the Safavid period, his books include "The Politics of Trade in Safavid Iran" (1999), "Portugal, the Persian Gulf and Safavid Persia" (2011) and most recently "Persia in Crisis: Safavid Decline and the Fall of Isfahan" (I.B.Tauris, 2012). He is co-author (with Willem Floor and Patrick Clawson) of "The Monetary History of Iran: From the Safavids to the Qajars" (I.B. Tauris, forthcoming).