The mid-1960s saw party chief Zhivkov "building bridges" himself with other Western countries.
The hallmark of Zhivkov's leadership has been his intense loyalty to the leaders of the Soviet Union.
Zhivkov was then an unknown functionary who had risen from the ranks of the Sofia party structure.
Unlike Chervenkov, however, Zhivkov based his government on the principle of collective leadership.
Zhivkov's rule, like that of his predecessor, emulated the Soviet model.
At the same time, this move increased Zhivkov's control over the party.
Internal problems continued to plague the Zhivkov government.
Zhivkov managed to avert the attempted coup d'etat and afterward strengthened his power base within the party.
Zhivkov also cited shortcomings of the prevailing piecework system and suggested some long-range remedies for the ills.