The first Western civilisation known to have developed the art of navigation at sea were the Phoenicians, around 4,000 years ago in 2,000 BC. 

Phoenician sailors navigated using primitive charts and observations of the sun and stars to determine directions. 

It would take many centuries before global navigation at sea became possible. 

By the second millennium BC, accumulated knowledge of stars and constellations began to facilitate more direct travel across the Mediterranean.

As increasing knowledge of astronomy began to spread and became more precise, navigation across open water became more possible and less risky. 

Detailed knowledge of the constellations, eclipses, and moon movements made navigation during day and night much easier.

Other developments include the use of sounding weights, which helped sailors determine the depth of water in given locations.

Weights would be lowered from a boat and would inform on the location’s depth. 

This knowledge could help with regards to how far ships were from land, as shallower seas could indicate that land was nearby or approaching.

By the late first millennium BC, new developments facilitated further navigation capabilities. 

This included the development of navigational charts and information passed down to sailors. 

These charts include types of notes and descriptions that likely assisted sailors over generations. 

Farther ventures were enabled by the development of scientifically and mathematically based methods and tools. 

It seems the Ancient Greeks did develop early incarnations of these instruments, perhaps including the Antikythera mechanism.

Found in 1900 near the Greek island of Antikythera, this metal contraption appears to be a mechanical device with gears and wheels.

Some experts believe it may have been used to aid navigation and understand the movements of celestial bodies in the third or second century BC.