The rank was first introduced in the Polish Army in 17th century to denote a Captain (rotmistrz) of the core banner of a regiment. By the end of the century, the title of the assignment became a de facto rank as such and started to denote the commanding officer of the entire regiment. In mercenary troops fighting in the ranks of the Polish-Lithuanian Commonwealth's army, the direct equivalent of the rank of pułkownik was oberszter, but in 18th century the rank was abolished and renamed to pułkownik as well.
Despite its etymology, in 20th century the regiments were seldom commanded by a regimentary. During the rules of Sanacja in the period between World War I and World War II a large number of officers was promoted to the rank, often for political reasons (the rule of Sanacja was even dubbed the government of the colonels because of that). During the Invasion of Poland in 1939, the Polish divisions were commanded by officers of many grades, from Colonels to three star generals. In fact 22 divisions out of 42 were commanded by Colonels in 1939. The pułkownicy (plural for pułkownik) did also command units of all sizes, from divisions down to mere battalions.
In the film The Eagle Has Landed, Michael Caine wears the uniform and insignia of a Pułkownik while in secret was a Oberst in the German Luftwaffe.