 Complete the following phrase:  A career-threatening development came in 1951, at which point Markov had still done little to modify his reputation as an unorthodox thinker. An increasingly nervous party leadership suddenly accused him of Titoism and Objectivism in January 1951. This may have arisen at least in part out of a reading of his 1949 habilitation dissertation on the complexities of nineteenth and twentieth-century rivalries in the Balkans. Markov was now excluded from the party. Irene Markov retained her membership. At the same time, he was stripped of his official and prestigious status as a . He was permitted to maintain his academic career. Nevertheless, his field of study abruptly changed from the nineteenth and 