The long sea voyages of the 16th century AD required better navigational aids. Throughout Europe, mathematicians and astronomers began to develop more accurate maps, charts and scientific instruments. Astronomical knowledge advanced when the Polish astronomer Nicholas Copernicus established that the Earth rotated on its axis and orbited the Sun (1534). His ideas were promoted by John Dee (1527-1608), a mathematician and astrologer, who advised Elizabeth I.

Throughout the century, the English gained knowledge from mainland Europe in the skills of printing mathematical texts, engraving maps, making scientific instruments, and surveying techniques. Astrolabes, invented by the Arabs, had been in use since medieval times to aid navigation. They, and the magnetic compass, were improved and joined by the quadrant (an instrument used for measuring altitude in astronomy). An English instrument trade was established in London by Humphrey Cole (about 1530-91), who was a skilled engraver of maps, illustrations and scientific instruments.

In contrast, clockmaking was dominated by immigrant craftsmen. They had been encouraged to settle in London by Henry VIII, Edward VI and Elizabeth. Many were Protestant refugees from France and the Low countries. Clockmaking techniques became more sophisticated, but there was no improvement in the accuracy needed for measuring longitude at sea.