The polska (Swedish plural polskor) is a family of music and dance forms shared by the Nordic countries: called polsk in Denmark, polka or polska in Estonia, polska in Sweden and Finland, and by several different names in Norway.  Norwegian variants include pols, rundom, springleik, and springar.[citation needed] The polska is almost always seen as a partner dance in 34-beatⓘ, although variants in 24 time, as well as in compound meters also exist.
 As suggested by the name, the roots of the polska are often traced back to the influence of the Polish court throughout the northern countries during the early 17th century. (Polska also happens to be homonymous with the Swedish word for the Polish language.)  This view is sometimes challenged by those who see earlier evidence of the musical tradition in Nordic visor or songs, that may have become grafted onto the newer foreign influences when the court dances began to filter out into the middle class and rural communities. In addition, some earlier triple meter dances and melodies may have evolved into the polska.[citation needed]
 The polska dances were likely inspired by court dances such as the polonaise or the 24 time minuet involving larger sets of people. Some[who?] see traces of the evolution from set dances to couples dances and from duple time to triple time in the minuets, still danced in some communities of Finland and Denmark.[clarification needed] In these, the dance starts with a large set of dancers dancing a slower formal section and ends with couples or foursomes dancing a faster, more energetic polska section. In the late 1600s it was common in northern Europe that only the slower Alla breve or 44 section of the music was written down on paper, as paper was expensive. The musicians were expected to be able to improvise a dance in 34 which was based on the same motivic material as the previous dance. The parts played in 34 were the ones evolving to the modern polska.
 In the prevalent 34 time form, polska dances were most common in Norway, Sweden and Swedish-speaking Finland, but with versions seen in Finnish-speaking Finland and in Denmark. It is best to discuss these dances by country as their regional histories, while contemporaneous, were quite varied and the dances known today differ significantly from one country to the next.
 Norway's dances show the most consistent living tradition, with unique local dances still performed socially today within specific regions or communities. There are two predominant broad types, each characterized by its own music, instrumentation, and dance tradition.
 In Sweden, the polska music tradition is continuous, with tunes and styles passed down through families, relatives, and neighbors. While styles have certainly evolved over time, the traditions and the roots can be traced back hundreds of years. In addition, through the 19th century a series of professional and semi-professional archivists travelled the land transcribing and annotating tunes. In contrast, however, polska dance traditions came under severe pressure during the industrialization of Sweden and, with few exceptions, succumbed entirely during the early 20th century. Most of what is known about Swedish polska dance comes from research conducted during the 1940s, 1950s, and 1960s. While some early films were located, researchers for the most part collected descriptions from older dancers—in some cases quite elderly ones—who had learned the dances in tradition from close relatives or others in an older generation.
 On the other hand, what is known about Swedish polska dancing indicates a rich tradition with perhaps several hundred unique variations of the triple time dances and, frequently, a parallel music tradition of uniquely styled tunes. Broadly, there are three styles of music for Swedish polska:
 A typical tune in the Swedish polska tradition shows a common structure, with two related eight-measure phrases, each repeated (a total of 32 bars constituting a single complete rendition of the tune), and the whole structure repeated two or more times. However, there are longer tunes (a storpolska or big polska has three or occasionally even four phrases) and there exist many tunes with odd numbers of measures per phrase and phrases that vary in length between parts. The first beat is not stressed except in
hambo a dance from the beginning of the 20th century.
 It is important that sharp lines and distinctions not be drawn. For example, all three styles of polska music form the historical traditions of Jämtland; sixteenth note polskas can also be found in virtually all areas of Sweden; and the placement of the second beat can be controversial even among fiddlers from the same community. Moreover, interesting counter-examples may be found for virtually any statement made in this article.
 A 56-page booklet and accompanying audio tape with 40 tunes. Cooperative venture of four Nordic institutes. Provides separate descriptions of music and dance traditions in the four Nordic countries in the local language, followed by complete translation in English.
Nyberg, B. (Swedish contributor);
Aksdal, B. (Norwegian contributor);
Koiranen, A. (Finnish contributor);
Koudal, H.K. & Nielsen, S. (Danish contributors);
Nyhus, S., Ramsten, M., & Häggman, A. (contributors, origin not specified).