In 1858, August Kekulé and Archibald Scott Couper independently published similar ideas regarding the tetravalence and self-linking ability of carbon atoms; three years later, the Russian chemist Aleksandr Mikhailovich Butlerov read a paper at the German Naturforscherversammlung in Speyer, which restated, clarified, and enlarged upon the ideas of Kekulé and Couper. In 1958, the centenary of the structure theory was celebrated in Chicago, London, Heidelberg, and Ghent; the celebrations in Moscow, Frunze, and Kazan took place three years later. For over a century chemists and chemical historians have disputed the origins of structure theory. Sometimes this activity has been confined to occasional sniping, but at other times determined battles have been fought. The polemic has never been characterized by cool and dispassionate discourse. Western historians have in general been unwilling or unable to master the extensive Russian literature on the question; the arguments of Soviet historians have often been clothed in Marxist rhetoric or otherwise influenced by political considerations.