Why was the cross staff important?

The cross staff was important in navigation during the late Middle Ages and the Renaissance because it allowed sailors to measure the angle of celestial bodies above the horizon. This tool enabled navigators to determine their latitude with greater accuracy while at sea. By aligning the cross staff with the celestial object and the horizon, sailors could take reliable readings, which significantly improved maritime navigation and exploration. Its use laid the groundwork for more advanced navigational instruments that followed.