From this agreement the slave traders reaped a harvest.  The trade centered at Liverpool, and that city’s commercial greatness was built largely on this foundation.  In 1709 it sent out one slaver of thirty tons’ burden; encouraged by Parliamentary subsidies which amounted to nearly half a million dollars between 1729 and 1750, the trade amounted to fifty-three ships in 1751; eighty-six in 1765, and at the beginning of the nineteenth century one hundred and eighty-five, which carried forty-nine thousand two hundred and thirteen slaves in one year.

The slave trade thus begun by the Portuguese, enlarged by the Dutch, and carried to its culmination by the English centered on the west coast near the seat of perhaps the oldest and most interesting culture of Africa.  It came at a critical time.  The culture of Yoruba, Benin, Mossiland, and Nupe had exhausted itself in a desperate attempt to stem the on-coming flood of Mohammedan culture.  It has succeeded in maintaining its small, loosely federated city-states suited to trade, industry, and art.  It had developed strong resistance toward the Sudan state builders toward the north, as in the case of the fighting Mossi; but behind this warlike resistance lay the peaceful city life which gave industrial ideas to Byzantium and shared something of Ethiopian and Mediterranean culture.

The first advent of the slave traders increased and encouraged native industry, as is evidenced by the bronze work of Benin; but soon this was pushed into the background, for it was not bronze metal but bronze flesh that Europe wanted.  A new tyranny, blood-thirsty, cruel, and built on war, forced itself forward in the Niger delta.  The powerful state of Dahomey arose early in the eighteenth century and became a devastating tyranny, reaching its highest power early in the nineteenth century.  Ashanti, a similar kingdom, began its conquests in 1719 and grew with the slave trade.  Thus state building in West Africa began to replace the city economy, but it was a state built on war and on war supported and encouraged largely for the sake of trade in human flesh.  The native industries were changed and disorganized.  Family ties and government were weakened.  Far into the heart of Africa this devilish disintegration, coupled with Christian rum and Mohammedan raiding, penetrated.  The face of Africa was turned south on these slave traders instead of northward toward the Mediterranean, where for two thousand years and more Europe and Africa had met in legitimate trade and mutual respect.  The full significance of the battle of Tenkadibou, which overthrew the Askias, was now clear.  Hereafter Africa for centuries was to appear before the world, not as the land of gold and ivory, of Mansa Musa and Meroe, but as a bound and captive slave, dumb and degraded.

The natural desire to avoid a painful subject has led historians to gloss over the details of the slave trade and leave the impression that it was a local west-coast phenomenon and confined to a few years.  It was, on the contrary, continent wide and centuries long and an economic, social, and political catastrophe probably unparalleled in human history.