The independence of Greek city states was due to what

There were a lot of factors that have contributed to the liberation of the Greek City States. They were then I conflict against the Ottoman Empire. The Greeks were supported by the Great Empire, Russian Empire, and other European forces. There were also lots of Greek revolt attempts to free themselves from the Ottoman. A secret organization was also founded to free Greece. After years of negotiation, Greek was finally announced as an independent state. Their independence day is celebrated every March 25.