My theory is that this must have taken quite some time
I'm not so sure about the time.... one of 2 things has happened as Chalco indicates it is originally Aztec
1. The Aztecs settled there and the city did not grow from 1 pop, Haddingtons pressure of 1.8 (currently) would have flipped the city to free and then its 1.8 per turn versus your 2.0 per turn meant you now get it.... but now pressure is higher
2. The Aztecs settled and the Zulu's conquered and it flipped with the same situation afterward.
The pressure formula is not that simple and its more about the ration of 1.8:1 but the key thing being its more.
Without a turn by turn screen shot or logs from the last 10 turns we will never know for sure but one of the above is the likely reason, both quite similar
I really do need to write that loyalty guide sometime. I'll update my signature to include the loyalty thread so at least there is a reference until then.
@BarbarianHunter is that an adequate explanation?
Kudos goes to @leandrombraz and @Virdrago , not me.
but Scotland seems to have enough to surpass Amani.
A 9 pop city at a distance of 8 is 20% of 9 which is 1.8 versus Amani's 2 which does not count distance
The irony is that once flipped to Norway the +2 is lost and is +1 for local pop so now its 1.8 vs 1 as opposed to 1.8 vs 2 before the flip
the diagram shows it was 9 turns due to the steady +2 accumulation by Amani... but Haddington must have grown in that 9 turns or it would be 16.2 (9*1.8)... seems like about 3 turns ago it grew. If you work it out you can only really get 14.8 or 14.6 but there is more complicated decimals involved I will not go into because we cannot work out.