Rudolph P. Matthee (Munroe Chaired Professor of History at the University of Delaware) noted in his book "The Politics of Trade in Safavid Iran: Silk for Silver, 1600-1730", dealing with the Safavid period (1501–1736), that the Iranians "had long despised Russians for their uncouthness". In the first half of the 19th century, Russia annexed large parts of Iranian territory in the Caucasus; With the Treaty of Gulistan (1813) and Treaty of Turkmenchay (1828), Iran was forced to cede what is present-day Azerbaijan, Armenia, eastern Georgia and southern Dagestan to Russia. This fuelled anti-Russian sentiment which led to an angry mob storming the Russian embassy in Tehran and killing everyone in 1829. Among those killed in the massacre was the newly appointed Russian ambassador to Iran, Aleksander Griboyedov, a celebrated playwright. Griboyedov had previously played an active role in negotiating the terms of the treaty of 1828. Soviet involvement in the Azerbaijani and Kurdish separatist movements also fueled negative attitudes.