First Ivan and his wife Praskovia had no children till Sophia was deposed. Then they had five girls of which three lived, Catherine, Ann and Praskovia. Peter can be understood well as CEO of Russia who thought his job as determined by God was to make Russia a financial powerhouse. For this the landlocked country needed a port. He tried initially to trade with Asia but the Black Sea was blocked by the Ottoman Empire so he went to Europe to get help to attack Turkey. No one was interested but the Poles were looking for an ally in attacking Sweden as Germany had pulled out. So Peter began to think of a European port and changing Russia to be a European power.The quick war lasted 21 years, he did not yet know the character of Charles XII the Lion of the North, but put Russia on the world stage. In the meantime he made the infrastructure, customs and dress of Russia compatible for European trade.
Elizabeth took over in a coup thirteen years after her mother's death because her doctor convinced her that if she did not she would be put in a convent. This was not true but her predecessor was winning a war with France and her doctor who was French, was paid to get her to depose the rule of the baby Ivan VI, well at least the regent who was winning battles.