Facts:   - death place: leiden , dutch republic    - known for: snell 's law    - caption: willebrord snel van royen -lrb- 1580 -- 1626 -rrb-    - death date: 30 october 1626    - field: astronomer and mathematician    - academic advisors: ludolph van ceulen rudolph snellius    - notable students: jacobus golius    - work institution: university of leiden      - birth date: 13 june 1580    - name: willebrord snellius    - nationality: dutch    - image: willebrord snellius.jpg    - birth place: leiden , dutch republic    - alma mater: university of leiden   Based on these bullet points, write a short biography describing the life of willebrord snellius .
Answer:
willebrord snellius -lrb- born willebrord snel van royen -rrb- -lrb- 1580 -- 30 october 1626 , leiden -rrb- was a dutch astronomer and mathematician , known in the english-speaking world as snell .in the west , especially the english speaking countries , his name has been attached to the law of refraction of light for several centuries , but it is now known that this law was first discovered by ibn sahl in 984 .the same law was also investigated by ptolemy and in the middle ages by witelo , but due to lack of adequate mathematical instruments -lrb- trigonometric functions -rrb- their results were saved as tables , not functions .the lunar crater snellius is named after willebrord snellius .