<P> The many voyages of discovery did not pay for themselves, and there was no funding for pure science in the Renaissance . Columbus had planned for Queen Isabella to set up trading posts with the cities of the Far East made famous by Marco Polo, but whose Silk Road and eastern maritime routes had been blockaded to her crown's trade . Of course, Columbus would never find Cathay (China) or Zipangu (Japan), and there was no longer any Great Khan for trade treaties . </P> <P> Slavery was practiced widely at that time amongst many peoples of the world, including some Native Americans . For the Portuguese--from whom Columbus received most of his maritime training--the profits from enslaving people had resulted in the first "financial return" on a 75 - year investment in Africa . </P> <P> Columbus enslaved five hundred and sixty people . The slaves were shipped to Spain; 200 died during the route back to Spain, and half of the remainder were ill when they arrived . After legal proceedings in the Cortes, some survivors were ordered released and to be returned to their las Americas homeland, whereas others were used by Queen Isabella as galley slaves . Columbus, desperate to repay his investors, failed to realize that Isabella and Ferdinand did not plan to follow or allow Portuguese slavery policy in this respect . Rounding up the slaves led to the first major battle between the Spanish and the native peoples in their homeland, called by Europeans "the New World". </P> <P> Columbus was eager to pay back dividends to those who had invested in his promise to fill his ships with gold . And since so many of the slaves died in captivity, he developed a plan while in the Province of Cicao on Hispaniola . Columbus imposed a tribute system, similar to that of the still - unknown Aztec Empire tribute on the mainland . All Cicaoan indigenous residents above 14 years of age were required to find and deliver a specific quota of gold every three months . Upon their doing so, they would receive copper tokens that they wore around their necks . Any Indian found without a copper token had their hands cut off and subsequently bled to death . </P>

How did the portuguese efforts to reach asia differ from columbus efforts