Mariner's astrolabes seem to have been in use from the 15th to the end of the 18th centuries. They evolved at about the same time as quadrants and cross-staffs. Their precursor, the astronomer's astrolabe and kamal, were either too cumbersome or not sufficiently accurate for sea-going use. An astrolabe found on the Passa Pau wreck is unique in that it is the only know/specimen coated with silver. It is dated 1645 and has the maker's name, Nicolao Rvffo, inscribed on it.