Marius,
Sorry, but we have to part ways here. LOL
Yes, that is a portion of the Codex Boturini, but your translation is COMPLETELY wrong.
First:
{ 13 days is the symbol of the Tecpatl ( the doubled-edged dagger ) plus another one day ( the dot )}.
What you have noted as a "Double-Edged Dagger" is actually the year "1 Flint" in the Aztec Calendar:
"One Flint" is the first year of the Mexica/Aztec Journey from Azcatitla (Aztlan) in 1324 A.D.. The above image is from the Codex Tira Tepechpan. That Codex is a linear calendar of Mexica/Aztec History. It begins before the journey in 1298 A.D., and ends in 1596 A.D. Several of the dates at both the beginning and end of the Codex are missing (worn away).
Second:
What you identified as symbolizing the seven tribes is not too far off. The "DOT" has absolutely nothing to do with this. The seven tribes are the seven houses (buildings):
There is ONE Ruling Tribe, and SIX Subordinate Tribes (one large temple/house and six smaller temples/houses)
I don't know how you managed to get a copy of that page of the Codex that has a line erased....but............... here is where the "DOT" comes in:
Your Pic........................................Every Other Pic of Codex
Okay, so here is what that part of the page means. This is a husband and wife. The husband is fully robed and sits on his ass, while his wife is behind him, and is on her knees. What you call a "DOT" is something attributable to her or her family. Maybe it is the symbol of her father who was a great warrior or nobility. Not enough detail to make out.
Here is the actual full page from the Codex Boturini:
..........and for those not familiar with Aztec/Maya Symbolism; The drawn footprints show the method and length of time/distance traveled:
...........and these symbols
are spoken words. Maybe the God of the Underworld spoke to the Mexica King and told him to leave Azcatitla.
Mike