When the African Union (known then as the Organization of African Unity) was founded, the leaders of that era understood that the success of their individual countries hinged on the success of the entire continent. Now, as the organization celebrates its 50th anniversary, we understand more than ever the key role that unity has played in Africa's past and must continue to play as the continent embraces this new wave of economic prosperity and international attention.Dr. Kwame Nkrumah, founding father of Ghana, the first sub-Saharan nation to gain its independence from colonial rule, famously said, "Our independence is meaningless unless it is linked up with the total liberation of Africa." This sense of solidarity was one of the driving forces behind the gathering of Dr. Nkrumah and other leaders from 32 African nations on May 25, 1963, in Addis Ababa, Ethiopia. Emperor Haile Selassie hosted that first ever African Summit, during which the organization was born.It is easy in this information age of search engines and social media, where protest and consensus are only a click away, to dismiss this decision to stand as one body in support of each other's mutual interests as unremarkable. But, in fact, it was a quite remarkable feat. It took a vision that extended beyond the problems and circumstances of right then and right there. It took the wisdom to know that all vestiges of domination had to be deconstructed. New structures and paradigms, ones that mirrored our indigenous traditions, had to be created.The divisions that had been created by colonialism, from artificial boundaries to purposely manufactured ethnic tensions, were all intentional impediments to African unity and, as a consequence, African liberation. Dividing, after all, is the first step toward conquering.The Organization of African Unity concerned itself with improving the living conditions of Africans on the continent, defending the sovereignty of newly liberated nations, as well as funding and fighting for the liberation of places still under colonial domination. It imposed sanctions on South Africa for its practice of apartheid and aligned itself with individuals and groups in other parts of the world, particularly the United States, that were engaged in a struggle for the equality of African people within the diaspora.Perhaps the most important mission of the Organization of African Unity, implicit in its every existence, was the recognition of Africans, regardless of origin, as brothers and sisters of the same soil. We were accepting the responsibility to be each other's keeper.But the priorities of the organization could only mirror the priorities of its member nations. There were years when some nations were being devastated by war, famine, ethnic strife and crippling poverty. The continent was fragmented. Many nations were too busy struggling for their own survival to take on the additional burden of being another country's keeper. And, not surprisingly, the despots and coup-makers who were looting their country's coffers balked at the idea of accountability.During those years, which are often referred to as "the lost decades," the Organization of African Unity seemed to exist in name only; many referred to it as a toothless bulldog. Nevertheless, everyone still recognized the need for its existence.In 2002, the Organization of African Unity was dissolved and replaced with the African Union. It was more than a superficial makeover. The post-colonial growing pains that had resulted in chaos and poor governance for many nations were now giving way to peace, democracy and the rule of law. And once again, we recognized the strength and power in our unity.The African Union is a well-structured organization with precise goals, a primary one of which is "to accelerate the political and socio-economic integration of the continent." In order to hasten this integration, eight regional economic communities were created: the Economic Community of West African States (ECOWAS) and the East African Community (EAC), to name just two.It is without a doubt that these subregional bodies have played a significant role in bringing economic stability. So much so that the majority of the nations listed as the world's fastest growing economies are on the African continent.Now that the majority of African nations are committed to the development of their democracies, the African Union is also better able to define its role when there is a need for conflict resolution. And because the challenges facing our nations are increasingly becoming ones that have no regard for national boundaries, challenges such as effectively enforcing laws to end the trafficking of drugs and human beings, addressing the impact of climate change, deforestation, desertification and land degradation, the African Union's member states will come to an agreement on how to grant the organization full legislative powers, while at the same time enabling nations to maintain their sovereignty.Just like the continent that it oversees, the African Union is a work in progress. As a student of history, I know that 50 years is a relatively short span of time, amounting to nothing more than a page in a history textbook. When considered in that context, the African Union has come a very long way since its inception -- three whole decades before the inception of the European Union -- and given the limitations that it has faced over the years, African Union has achieved a great deal.At that first African summit in Addis Ababa, Emperor Haile Selassie said, "May this convention of union last 1,000 years." With the renewed sense of potential on the African continent, indeed it shall.John Dramani Mahama is the president of Ghana.