The New Holy Land

Christopher Columbus failed to secure backing for his planned voyage to find a western route to the Indies from John II of Portugal and Henry VII of England. In this timeline, his meetings with Ferdinand and Isabella went much the same, with many in their court deeming his plans impractical and costly. After trying numerous royal courts and meeting with repeated rejection, Columbus sought backing from a more unusual group, the Knights Hospitaller, currently based in Rhodes. They had the ships to fit out an expedition and, though not as well off as they had been in previous centuries, possessed enough income to fund a few voyages. More importantly, with their original goal of Jerusalem firmly under muslim control and the Ottomans pressing in on all sides, any options of land and wealth looked more tempting.

This POD would result in Columbus sailing under the cross of the Hospitallers and establishing a new crusader state in the Americas, known in this timeline as Santerre (from French Sainte Terre - Holy Land).

Outline and Explanation
Being such a relatively small group and without the resources of a monarchy in the time period, the Hospitallers do not take the role of Spain in colonisation much of the Americas. Spain, Portugal and later France, Britain and the Netherlands still continued along similar lines to OTL, and the resultant map of the Americas looks familiar. However, in later centuries the order's influence in the Caribbean and Mesoamerica becomes more pronounced, albeit mixed with local indigenous populations and the cultures of its immigrant members, which it continues to draw from varied European states.

Although under increasing pressure from colonial empires, it manages to secure its independence, and we see a shift from company rule to nationhood, similar to the East Indian Company and Raj in India.