Mazurs are Polish ethnic group from Mazovia (Catholics) or East Prussia (Protestant), the latter often called Masurians in English.
Their name derives from the Lekhitic tribe of Masovians (Mazowszanie) who gave their name to the land of Masovia (Mazowsze). In the Middle ages the inhabitants of the northern part of Masovia were called Mazurzy. Between the XIV and XVII centuries, settlers from northern Mazovia moved to former teritories of Old Prussians following their conquest by Teutonic Order.
Because of the influx of Masovians into the southern lake region of Prussia the area started to be known as Masuria (Polish:Mazury, German:Masuren). During the reformation Masurians - as the whole population of Ducal Prussia - became protestant, while Masovia remained catholic.
Example of 19th century germanisation:
Data from Oletzko County, a historical East Prussian county with capital in Oletzko, populated by Masurs. In the process of germanisation, the number of Polish-speaking people decreased:
1818 - over 90% of population
1852 - 65%
1861 - 58%
1890 - 46%
1900 - 33.5% (Prussian census)
1890 - 19%
In 1888, the Polish language was completely forbidden in schools of all levels.
See Masuria for more detail
Mazur (Masurian) is also the name of one of the five major dialects of the Polish language. Its variations are spoken in the countryside of northern Masovia and until about 1950 were commonly spoken in Masuria.
Mazur is also a traditional Polish folk dance from Masovia.
See also: Mazurka
Mazur (feminine: Mazur/Mazurowa, plural Mazurowie) is the 14th most popular surname in Poland (66,773 people)
Mazur surname in voivodships: