The 13.000 more men Christopher Columbus brought with him from Spain to Hispaniola in 1494, quickly realized that months will go by without Spanish ships with goods and provisions from Europe. With nothing to eat, and not use to cultivating, often they would pillage the Tainos' villages in search of food.

Frequently, hundreds of Spaniards would descend on a village, for a few weeks, demanding hospitality from the Tainos. Not only did they forced the natives to give them foods, they seem to eat much more than a Taino would. The Spanish occupants not only, ate more they also ate the crops that were not ready to be harvested. They ate the manioc, the potatoes and other crops that the native peasants would have left in the grounds for another 6 months; so after hundreds of colonists left a town, famine usually follows, and the natives died in the hundreds.    

The Taino/Arawak population quickly decimated. Not only did the Europeans introduced new infectious diseases to which they had no cure for; diseases such as smallpox, typhus, influenza, measles and diphtheria; the natives also were not used to the harsh treatments they were subjected to. Before, they only cultivated just enough to feed their small villages, now they had an additional 13.000 mouths, plus they were compelled to work long hours under the sun; digging mines in search of golds and other precious metals; forcefully converted into a new religion; Catholicism, and when they refused they were burned at the stakes.         

Guacanagari, the same Cacique who rescued Christopher Columbus and his men when Santa Maria had sunk, and gave him a piece of land to settle,  famously quoted before escaping:

"I'd rather eternally burn in hell, than to go to a heaven where I would find people of your kinds"

 By 1517, the natives went from 3 millions to less than 10.000.

The kind hearted priest Bartolome de las Casas, appointed by queen Isabella of Castille to oversee the horrible living conditions of the natives, horrified by the idea of an entire extermination of the natives, the priest recommended something that instead of helping, made it not only worse for the Tainos/Arawak population of Haiti, but completely changed the course of human history.

Bartolome de las Casas recommended the importation of African slaves to help and replace the natives who have died.
So there you have it. The Catholic Church through it priest and the queen of Spain launched the Atlantic Slave trade, a trade that would expand to every corner of three continents and last for over four centuries.