Along with the fact that the infrastructural and industrial levels of the African colonies was never really developed by Europeans, the many various and opposing ethnic groups had no one to keep them in check now. As a result many civil wars took place between different religions, specific religious denominations, and specific ethnic groups of said religious denominations. Also nearly all of the leaders that broke free of European rule were woefully unprepared to lead a country both governmentally and economically. All of these factors are what lead to Africa's current problems.
Sparta was known for their extreme war skills and judging by history Athens was a capital city and most of the soldiers of Greece came from Sparta I guess
