This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Huswirt Enchiridion artis numerandi s. d. . Book Huswirt Johannes Enchiridion artis numerandi Veneunt Reginaldo caldario sub homine syluestri in via ad diuum Iacobum Lutetiae lat it Enchiridion artis numerandi parvo admodum negotio omnem calculi praxim docens in integris minutijs vulgaribus proiectilibus regulis aliquot mercatorum