Sudan has a rich and unique musical culture that has been through chronic instability and repression during the modern history of Sudan. Beginning with the imposition of strict Salafi interpretation of ''sharia'' law in 1989, many of the country's most prominent poets, like Mahjoub Sharif, were imprisoned while others, like Mohammed el Amin (returned to Sudan in the mid-1990s) and Mohammed Wardi (returned to Sudan 2003), fled to Cairo. Traditional music suffered too, with traditional Zār ceremonies being interrupted and drums confiscated . At the same time European militaries contributed to the development of Sudanese music by introducing new instruments and styles; military bands, especially the Scottish bagpipes, were renowned, and set traditional music to military march music. The march ''March Shulkawi No 1'', is an example, set to the sounds of the Shilluk. Northern Sudan listens to different music than the rest of Sudan. A type of music called Aldlayib uses a musical instrument called the Tambur. The Tambur has five strings, is made from wood and makes music accompanied by the voices of human applause and singing artists.