(bAmsterdam, 1629; d Amsterdam, 1704). Dutch violin maker. He is reputed by some to have been a pupil of Nicolò Amati, but this seems unlikely; he probably became familiar with good Italian instruments that had been taken to Amsterdam, perhaps also those of the Austrian maker Jacob Stainer. Jacobsz was the most celebrated of the Dutch makers, but instruments made entirely by him are quite rare. His copies of the Amati ‘grand pattern’ achieve the ultimate in visual elegance, the sweeping outlines highlighted by the use of jet-black whalebone for the dark strips of purfling. The varnish is of Italian quality. He spelt his name either Jacobsz or Jacobs on his labels. Through his marriage in 1676 he acquired a stepson, Pieter Rombouts, who eventually took over from him; Rombouts's work is increasingly evident in Jacobsz's later instruments, especially in the broad purfling.