Peter I and Ivan V (1682-96)
When Tsar Fyodor III died in 1682, he left no children and thus no clear heir to the throne. A Boyar Duma, or council of nobles, proclaimed Fyodor's two half-brothers, 10-year-old Peter I and 15-year-old Ivan V co-Tsars. A special dual-seated throne was built for the two.
Ivan was named the senior Tsar, but was physically and mentally handicapped and unable to rule. Fyodor's sister, Sophia Alekseyevna acted as regent and ruled like an autocrat for seven years. In 1689, when he was 17, Peter decided to seize full power. Sophia tried to resist by provoking an uprising, but was overthrown. She was forced to enter a convent and was stripped of her title as a member of the royal family.
Peter's mother, Nataliya Naryshkina, acted as regent until her death in 1694. Peter became sole ruler of Russia in 1696, when Ivan died.
Tsar Nicholas II and Prime Minister Stolypin (1906-11)
Nicholas II appointed Pyotr Stolypin as prime minister in July 1906, a time of revolutionary upheaval in the Russian Empire. Leftist organizations were waging a campaign of assassinations against the ruling elite. Nicholas granted Stolypin widespread powers to deal with the unrest -- making him close to an effective co-ruler.
And Stolypin was not hesitant to use his authority. He set up a new court system allowing for expedited trials for suspected revolutionaries -- resulting in thousands of executions. He changed the voting system in the Duma, giving more weight to the nobility and wealthy, to make it more supportive of the government. And he introduced land reforms to quell rural unrest.
Stolypin was assassinated in September 1911 by a leftist radical while attending a performance at the Kyiv Opera House.
Secretary-General Brezhnev and Premier Kosygin (1964-80)
When Soviet leader Nikita Krushchev was deposed in 1964, Leonid Brezhnev became secretary-general of the Communist Party and Aleksei Kosygin was named premier.
The two differed over economic policy, but nevertheless worked reasonably well together. Kosygin sought to reform the Soviet economy, moving away from heavy industry and military production in favor of light industry and consumer goods.
Over time, Brezhnev's power steadily increased and he eventually became the undisputed ruler of the country. Kosygin fell ill and resigned as premier in October 1980 and died two months later.