Perhaps the most baffling period of early Quendoran history is the generation roughly spanning the years 150-175 GUE. Despite the traditional and highly well-grounded dating of Zylon the Aged’s reign from to 55 to 398 GUE, some lesser traditions insist on naming a Lord Kwisko, the great-great-grandson of Entharion, as king of Quendor during the 25 year period noted above. How these two traditions can be reconciled has been a matter of some great scholarly debate. All sorts of theories abound, ranging from the unlikely idea that Kwisko was nothing more than an alternate monikor for the aged Zylon to the theory suggesting that Kwisko was in fact pretender to the throne of Quendor, and advocated the overthrow of the central power at Largoneth. However, it is clear from the lack of evidence either way that Kwisko's impact on the history of the era was minimal, and perhaps only local at best.

Antor Zilbarion, the main proponent of the Pretender-King Theory, notes in his book “Lord Kwisko, Pretender” that much of the surviving epic oral poems on Kwisko originate in a very narrow geographic area covering only the Mauldwood and the plains stretching from that forest to Borphee proper, and thus it might be reasonable to conclude that Kwisko himself was some sort of local political leader who gained considerable influence within that area, but never gained widespread recognition elsewhere.

Some historians point out that there are no original sources pointing out who was the king the entire time attributed to Zylon. Many other recent historians, who would hurry to disprove Zylon the Aged's tremendous lifespan, have adamantly stood upon the kingship of Kwisko as the main refuting component. Another element is that many king lists only give the final date of each reign, and thus a section of the list could be missing, utterly removing the need to give Zylon an unusually long life span. Other contenders seek to stand upon the unstable grounds that this period referred to the Zylon family, and not to one particular personage.

Despite these doubters, who like to deny the seemingly impossible for the sake of scientific rationality, there is no solid evidence to reject the well-preserved writings of Zilbo I, who provides us with the deeds of Zylon the Aged that range even to the years prior to his centuries of kingship, in “I Can’t Believe You’d Ask Such a Stupid Question about Zylon the Aged.”