The violin-type pegbox was replaced about 1600 by a flat, slightly reflexed head with rear tuning pegs; in the 19th century, metal screws were substituted for the tuning pegs. The early tied-on gut frets were replaced by built-on ivory or metal frets in the 18th century. The fingerboard was originally flush with and ended at the belly, and several metal or ivory frets were placed directly on the belly. In the 19th century the fingerboard was raised slightly above the level of the belly and was extended across it to the edge of the sound hole.