Okay, this makes sense now.

Yesterday my mind was blown when I discovered that the entire run of the old Marvel comic John Carter Warlord of Mars takes place between two paragraphs in Burrough's original A Princess of Mars. Well, here are the paragraphs in question:

Three weeks later, Mors Kajak and his officers, accompanied by Tars Tarkas and Sola, returned upon a battleship that had been dispatched to Thark to fetch them in time for the ceremony which made Dejah Thoris and John Carter one.

For nine years I served in the councils and fought in the armies of Helium as a prince of the house of Tardos Mors. The people seemed never to tire of heaping honors upon me, and no day passed that did not bring some new proof of their love for my princess, the incomparable Dejah Thoris.

So that paragraph break allows for nine years of Martian adventure. 28 comic book adventures don't hardly begin to fill that gap. Now that I think about it, the rest of the John Carter novels are probably set in that same space between the wedding and the sudden passage of nine years.