Russo-Persian War: At the start of the war Persia was already in chaos and was about to collapse. Peter the Great took advantage of this and invaded Persia. The war went from 1722 to 1723. In the end, Russia won and gained lots of land from Persia but had lost a lot of men from fighting. After Peter died, his heirs struggled for power and all the lands that Russia had conquered were given back to Persia.