The ensembles include flutes, zithers, gongs, drums, fiddles, lutes, cymbals and xylophones. Ancient musical instruments evolved into many variations, such as lutes, zithers and arched harps. The Vikings are known to have played instruments including harps, fiddles, lyres and lutes. Cymbals gained popularity, along with more advanced trumpets, clarinets, oboes, flutes, drums, and lutes. Excavations have uncovered several musical instruments, including harps, lutes, double oboes, and a few others. Percussion instruments, lyres and lutes were added to orchestras by the Middle Kingdom. Medieval musical instruments included horns, trumpets, lutes, psalteries and cymbals. Harps, lutes, and other handheld instruments are more typical of early 17th-century music. Instrumental polyphony is achieved primarily by lutes and fiddles. Ngoni (lutes) and balafon (xylophones) are also common. Bowed instruments such as the violin, viola, baryton, and various lutes dominated popular music. The most ancient lutes had long necks. The oud is very similar to modern lutes, and also to Western lutes. In later Baroque lutes two upper courses are single. He was among the first to apply Greek musical theory to Central Asian-Arabian short lutes.