Holy roman empire: all central europe founded by charlemagne in 800, again in 12th century, always in existence, emperor elected. Great chain of being: a powerful visual metaphor for divinely inspired universal hierarchy ranking all forms of higher and lower life. St brendan: celtic saint and hero of legendary atlantic voyages. Prester john: legendary christian king/priest king who was believed to rule over a vast kingdom of great wealth in asia or africa during the middle ages. Treaty of tordesillas: treaty between spain and portugal that divided the non-christian world into 2 zones of influence. Ferdinand magellan: portuguese navigator for spain, commanded the navigation that was the first to circumnavigate the world. Hernando cortez: spanish conquistador who defeated the aztecs and conquered mexico. Francisco pizzarro: discovered incans and conquered them. Aztecs: central mexican civilization that was at its height at the time of the spanish conquests on the early 16th c.