Persian classical music is largely improvised, and this improvisation is based on a series of modal scales and tunes that musicians spend many years memorizing as part of their long training. Traditionally, there was a very close relationship between pupil and master, or ostad (a word which, along with other Persian words, was also taken up by musicians in North India), and teaching would usually take place in the ostad’s home. During the course of the twentieth century, most teaching was taken over by conservatoires and universities. The music is largely an oral tradition, and the emphasis is still on strict rote memorization.