As was traditional at the time, Kirtan was also often accompanied by the Pakhawaj (Mridangam) or Dholak, popular percussion instruments of the 15th and 16th Centuries. The Taanpura, though not considered essential in 16th century Indian music, became increasingly prominent, over time, in providing a droning background, especially in classical styles. Mirasis who sang and performed Gurbani Kirtan, were renamed Rababis, and became the established singers of the Guru’s Court (in 1521 at Kartarpur). Later, the professional Rababis became largely displaced by amateur Sikh musicians and bards, known as bhatts and ragis, especially during the time of Guru Arjan Dev Ji, when the Golden Temple became the official Court of the Guru.
Source: Raj Academy