Peter the Great was, among other things, a military reformer of note. After traveling the world he decided to reorganize the armed forces of Imperial Russian. He started the now 300 year old Russian navy from scratch. (Its first boat is still on display-the Russians never throw anything away) He disbanded the hated Strelsty units that dated from medieval times (and had more than once tried to kill the young tsar). He introduced modern military drill and courtesy including a rank system based on the Prussian Army that is still used to this day (ah-ha, this is why Russian troops are always goose-stepping). Peter the Great led his new army and navy in a series of wars that were to last some 25 years and defeat for the first time the vaunted armies of the Swedish military genius Gustavus Adolfus. He also smacked around the Ottoman Turks and gained huge tracts of land that is still part of Russia today.
One of the more interesting and indeed, enduring, military reforms of Peter the Great was the Imperial Guard. Peter was always very interested in all things military and was given a unit of soldiers to 'play' with as a child. As time passed these 'playthings' grew into a force of two modern infantry regiments complete with artillery and would compete in mock battles with each other -even going so far as to inflict very real casualties. When Peter became tsar he formed his toy soldiers into a new Lieb Guard (Life Guard) in 1683.
This force would protect the Romanov monarchy for the next 234 years, serve on both sides of the Russian Revolution and Civil War, and then go forward to continue to exist to this day in one form or another.