The earliest explorers and men who sailed on the open sea were well versed in astrometry, as they primarily had to rely on the position of the stars to navigate their way in the ancient world. This had several distinct disadvantages, as it required advanced knowledge of the way celestial bodies moved in the sky, and it was also useless when said bodies could not be seen. That meant that these navigation methods would be useless during the day, or if there were any clouds in the sky while the sun was down.
After the compass was invented, these problems were no longer applicable to navigation. Not only could it be used at all times during the course of a day, but it was simple and easy to read. This allowed for sailors to traverse deeper into the wide expanse of the ocean, as they didn’t need to rely on landmarks to guide their position.
Evidence of compasses exist from around 2500 BCE from multiple civilizations, such as the Greeks and the Chinese. Much different from the hand held devices of today, magnetic lodestones were suspended so that they could spin freely. The more modern precursor was invented during the Han dynasty, but wouldn’t be used explicitly for navigation until around 1,000 AD. It is unknown if this technology was passed to the west from the east, as there seems to be evidence that the Europeans were able to create the technology on their own, albeit at a later date.
With navigation becoming easier and more reliable, the compass was an important factor that led into the Age of Discovery. Along with advancements in ship building, this allowed explorers, merchants, and missionaries to traverse to the edges of the known world, spreading goods and beliefs toward regions they had never been able to reach before. Who knows what the landscape would look like if it hadn’t been invented for a couple of centuries?