In the early 1400s, a new number system was introduced into Europe from Arabia.
The old Greek and Roman systems made calculations very difficult.
Using the new Arabic numerals, only 10 different digits were needed to express any number.
People at that time still depended on celestial movements to determine medical treatment and to predict the future. Measurements of these movements were now much easier.
At the same time, sea travel was becoming much more important for commerce and exploration.
Ships were getting larger and traveling farther away from home, sometimes across the vast Atlantic Ocean. The science of navigation was vital to the success of these voyages, and the ships relied on astronomical tables to guide them.
Astronomical discoveries were also helping the powerful churches create more accurate calendars so that holy days could be celebrated properly.