How old is the veena?

The Saraswati veena descends from earlier lute forms, the kinnari veena in Sambamurthy's account. Its fixed 24-fret form evolved at Thanjavur during the reign of Raghunatha Nayak, and Sambamurthy credits the design to Govinda Dikshita, a minister at the court. Earlier veenas had fewer frets, and those frets were movable.