What was the major difference between the voyage of the Portuguese explorers and Columbus?

The main difference between the exploratory voyages of the Portuguese and the voyages of Christopher Columbus was the direction in which both voyages began: while the Portuguese decided to set sail towards the southeast, bordering the African continent with the aim of thus reaching the Indian Ocean (knowing that the African continent, after passing the Cape of Good Hope, joined that ocean); Christopher Columbis, based on his conviction that the Earth was round (and not flat, as various theories of the time said) set sail to the west, seeking to go around the world that would allow him to reach the markets of China and India.

one of the main reasons was definitely slavery. back in 1861, republican abraham lincoln was elected and ended up being a major influence in the slavery business. slavery greatly affected the texas economy because back in 1845 during the annexation of texas, slaves became a big part of the texas population. many texans that were in favor of the secession influenced groups through party ties.

oil! is what i am assuming