Henry VIII, main part of the triptych

Once the Nahuatl chronology is in place and the king and island on the outside are shown to relate to Henry VIII and his situation as of 1528, interpreting the central panels is amazingly easy. The three main topics in the triptych are the conquest of Mexico, shown year by year in annals style and in hieroglyphics, problems with Martin Luther, shown in an equally obscure fashion, and Henry VIII's pending divorce, which is shown as a matter of big, simple issues that do not go away.
To start with, the left panel shows Adam and Eve, with no replacement in case Adam wants to try again with another woman. On the other hand, the right panel shows the sack of Rome (labeled in the Nahuatl chronology as happening in 1527) which would continue to affect the divorce one way or the other.
The most obvious divorce-related image in the center panel is the scene showing a woman inside a sphere, where the man outside the sphere cannot see another man who is inside the sphere with her. Was Katherine of Aragon's marriage with the king's older brother consummated? Who knows.
Artistically, the late Hieronymus Bosch (who died in 1516) is less important than the Franciscan Thomas Murner, who had a system of teaching based on sets of pictures, sometimes playing cards. The idea was that pupils could connect words to pictures of things they liked (horses, spiders, scorpions) and also remember larger, complicated pictures. Like the "new math" of the 1960s, it made no sense to anyone but the pupils, which may have made it more effective. Murner was also the one to translate Henry VIII's book into German. The humorous side that José de Sigüenza called macaronic seems to derive more from the late Peter Martyr who was Katherine of Aragon's tutor, and the late Antonio de Nebrija.
The present interpretation has been going along CSI-style, starting with the iconographic equivalent of looking at footprints under a microscope, but like a CSI mystery, it is revolving into a situation where some of the most implausible or fragmentary early interpretations turn out to be correct. These include:

• Paul Vandenbroek's 1000-page explanation of how (paraphrasing very loosely) the center panel shows marriage as boring but necessary;
• Isabel Mateo Gomez's identification of the person at the lower right as John the Baptist (since he was beheaded for objecting to a case of bigamy);
• Derek Wilson's identification of the skull in Holbein's Ambassadors as a pun where memento mori stands for memento (Thomas More)i;
• the anonymous French inventory that described a tapestry version as follows: "…Une aultre pièce en laquelle est figuré le Monde, l'Enfer et le Paradis terrestre, enchassé en ung tableau contrefaict de menuyserie comme les précédans, sauf qu'il y a deux colonnes par voye…" The two columns made it absurdly obvious that it showed Charles V's view of the world. The associated motto "plus ultra" (farther out) applies fairly well to the process of interpreting the very complicated picture.

Also, to add something new, the fish in the center has to represent John Fisher. Saint Thomas More and Saint John Fisher, both shown as important here, were canonized later.
The artist is still unidentified but it is starting to look as though the triptych went to Breda with Hendrick III of Nassau (as various scholars claim) rather than his wife Mencía de Mendoza since Hendrick was a crony of Charles V and seems to have had more of a sense of humor than his more literate wife.
For those who long for CSI type evidence, the paw of the lizard that was discovered when the right panel was x-rayed has a remarkable resemblance to the hand of a small boy in a tapestry that was made for Hendrick III, based on a design by Raphael and Giovanni da Udine but more ridiculous than the average Raphael.