What is the most important reason that greek fell apart

Primary Causes
Greece was divided into city-states. Constant warring between the city states weakened Greece and made it difficult to unite against a common enemy like Rome. The poorer classes in Greece began to rebel against the aristocracy and the wealthy.

In two early battles, the army lost control of Boston but then regained it. Patriots attacked British at Fort Ticonderoga on May 10, 1775, to seize large supply of weapons. Colonial forces fortified Breed's Hill to prevent British escape from Boston. The colonies formally declared their independence from Great Britain.