Their name derives from Lekhitic tribe of Masovians (Mazowszanie) who gave their name to the land of Mazovia (Mazowsze. In Middle ages the inhabitans of northern part of Masovia started be called Masurians.
Between XIV and XVII centuries settlers from northern Mazovia moved to former teritories of Old Prussians following their conquest by Teutonic Order.
See also: Mazurka