His 1628 map of Africa included an illustrated depiction of the seemingly ageless Prester John; in this scanned image, one can observe that the passing of almost six decades between grandfather and grandson resulted in few changes to the ways in which Prester John had been imagined by European cartographers.

The 1628 Mercator map again depicts a seated Prester John with a cross, and the mythical potentate still faces east. The priest-king in this image wears a flowing royal robe instead of what appears to be a mandilion on Prester John in the 1569 map. On the head of Prester John is a more elabroate crown in the 1628 image, implying at least a sense of continuity in the perceived importance heldy by the illustrator twoard the priest-king in continental and regional affairs. Both Mercator maps... provided a prominent place for the kingdom of Prester John. While some Europeans in the late sixteenth and early seventeenth centuries had begun the process of moving away from a strong belief in the power and wealth of Prester John, clearly the notion of this mighty priest-king remained a source of fascination for many learned Europeans, and the Mercator maps serve as evidence of this continued allure. Yet despite his innovative techniques, Gerardus Mercator and his work remained relatively unknown beyond a small circle of geographical and cartographical experts, and it would take the efforts of another Flemish cartographer to bring Mercator's projections to a wider audience.