The Greeks established colonies for over

The Greeks established colonies for over 400 years.

Explanation:

The Ancient Greeks were well known for living along the coastlines, creating small colonies, and constantly being engaged into maritime trade. From what is known for the ancient sources the first Greek colonies occurred during the 8th century BC and since then until the rise of the Kingdom of Macedon in the second half of the 4th century the Greeks managed to create around 500 colonies.

The colonies, once established, were in general becoming independent city-states of their own. While the first colonies were established close to the Greek mainland, like in the southern islands of the Aegean and Adriatic Sea, later the Greeks managed to create colonies along the coasts of the Black Sea, Northern Africa, Sicily and southern Italy, southern France, eastern and southern Iberian Peninsula, creating a large and highly functional trading network. This all came to an end with the rise of power of the Kingdom of Macedon when the Greek city-states were conquered and lost their power.