Why successful explorers were not always strong leaders

Which explorers serving Spain under the Catholic Monarchs, Philip I and Joanna, and Charles V were the strongest leaders?

No top five is chosen; the assessment questions whether the qualities that secured royal backing also made these explorers good leaders.

The requested top five receives no selections. The skeptical assessment separates royal favor, religious commitment, and a desire to travel from the ability to command people well. Pay and the prospect of adventure are offered as reasons followers might join an expedition without trusting its leader. James Cook becomes a later comparison in this distinction between exploration and leadership, rather than an example from the Spanish reigns in the question.