Based on numerous iconographical sources, and the surviving neck and pillar of a medieval harp in the Louvre Paris.

This harp has a sycamore neck and pillar, and a willow soundbox. It comes in two versions: single row with 20 strings tuned f-d”’, and 'arpa doble' with two rows of strings tuned in opposite unison pairs as in the tryptich circa 1390,  in the Monasterio de Piedra , Spain. 

This harp is now also available as a larger model with range C-d'''.