Keeping track of the timeline

Many posts have been written about the internal consistency of the Book of Mormon. Those who believe that a poor young farmer invented it and dictated it at record speed without notes or manuscript, would need to answer why he made it so complicated for himself. A collection of revelations of the type "thus saith the Lord" should do. But in addition to the theology, we get complex interwoven stories, about 200 personal names, a consistent geography with an additional 100 names, internal references and a timeline. Some examples of the latter are given in this post. We have seen some examples of long side stories resuming. Another one of those is the flashback to the Lamanite mission of the Sons of Mosiah. In Alma 16:21

thus ended the fourteenth year of the reign of the judges over the people of Nephi.

In the next chapter, Alma meets the sons of Mosiah. In 17:4

And they had been teaching the word of God for the space of fourteen years among the Lamanites

This is consistent with Mosiah 28, where the Sons of Mosiah leave on a mission to the Lamanites, right before the start of the reign of the judges in Mosiah 29, i.e. the first year. In Alma 17, when Alma meets his old friends, the flashback starts and we follow them on their mission to the Lamanites. This story is told over 10 chapters and in Alma 27, we get a second account of their meeting. After that, in Alma 28:7:

And thus endeth the fifteenth year of the reign of the judges over the people of Nephi

Since the fifteenth year ends after they meet and the fourteenth year ends before they meet, this is all consistent, but due to the flashback, these two are 12 chapters apart. In order to keep the timeline straight, the author needs to not only know what happened in previous chapters but when.

Some other examples:

Mosiah's reign

Mosiah 6:4: 

And Mosiah began to reign in his father’s stead. And he began to reign in the thirtieth year of his age, making in the whole, about four hundred and seventy-six years from the time that Lehi left Jerusalem

Then 33 years later in Mosiah 29:46

And it came to pass that Mosiah died also, in the thirty and third year of his reign, being sixty and three years old; making in the whole, five hundred and nine years from the time Lehi left Jerusalem

These are not numbers just thrown out there. Anything else in Mosiah 29 would make it inconsistent with Mosiah 6.

The reign of judges

The reign of judges started in Mosiah 29 and with it a new time reckoning. Mosiah 29:46:

making in the whole, five hundred and nine years from the time Lehi left Jerusalem

So the reign of the judges started 509 years after Lehi left Jerusalem. Then in 3 Nephi 1:1, 80 chapters later:

Now it came to pass that the ninety and first year [of the judges] had passed away and it was six hundred years from the time that Lehi left Jerusalem

509+91=600

Mormon's age

4 Nephi 1:48

when three hundred and twenty years had passed away, Ammaron, being constrained by the Holy Ghost, did hide up the records which were sacred

Mormon 1:2

about the time that Ammaron hid up the records unto the Lord, he came unto me, (I being about ten years of age…)

So Mormon was about 10 years old when 320 years had passed, and in Mormon 2:2

In my sixteenth year… 326 years had passed

And it adds up again. It always does. The Book of Mormon authors have been thorough with their time-keeping. Or was it just Joseph Smith making this up without notes or manuscript? Ummm, no!