Successful build - Chance fights ever on the side of the prudent.

Link to build: https://jenkins.wildfiregames.com/job/vs2015-differential/943/display/redirect

Successful build - Chance fights ever on the side of the prudent.

Link to build: https://jenkins.wildfiregames.com/job/macos-differential/39/display/redirect

Successful build - Chance fights ever on the side of the prudent.

Link to build: https://jenkins.wildfiregames.com/job/docker-differential/1461/display/redirect

I thought the difference lay in the setup of their armies: quality over quantity for the Spartans and vice versa for the Persians.
The Mauryas don't seem to follow this logic and it seems to be that they indeed have the bonus due to the sheer size of their former empire (forum post).

I cannot find myself agreeing with the idea, I think it goes the opposite way of what should be done (making civs more equal instead of more distinct).
The idea was that civs play and feel differently. This is one of the ways this was expressed. The game should be balanced, and a player should have a chance of winning with all civs, but that doesn't mean that they must have equal means of getting there.

all are supposed to have equivalent positions and equal chances to win. Having these civ-specific population bonuses flatly contradicts 0 A.D.'s “what if ...” premise.

With this argument one should remove all civ bonuses and differences.

To clarify, I'm certainly in favour of differentiating civilizations, aiming for a distinct feel each, and adding civilization bonuses, amongst other things, to achieve that. However, ensure those civilization bonuses are reasonable and historically informed. These pop cap bonuses (pop cap ought to be a map setting) seem to be merely a civ bonus for civ bonus' sake; as is the case for the Iberian starting walls (another whimsical choice that is partially map dependent): everyone built walls, the Iberians not more frequently or better than anyone else.
If a certain nation was known for fielding large armies, then give them a discount on training time (already the case for Persians), unit costs, barracks, population per house, farming bonus, whatever, but make it something specific to the civ in question.
That Persian land traders have +25% trade gain (Darius' initiatives to build royal roads and caravanserais and issue a new, reliable currency, the Daric, greatly boosted trade, both within the Persian empire and far beyond) or that Mauryan city walls cost wood instead of stone and are consequently weaker (Indians were not known for their stone architecture, contrary to Persians and Greeks) are in my opinion good civilization bonuses. Making Mauryan infantry cheaper but with less armour would be another one (Indians were not known for wearing body armour, whereas Roman infantry was known for their chainmail).

give them something specific to the civ in question.

If I understand this is the only argument for this to be removed?

I.e. this argument:

an accident of history: the size of populations has nothing to do with anything specific to the civilizations: a large area can simply support a large population: had the Mauryas lived in the Peloponnese, they would have had only a small population, and had the Spartans lived in India, they might have conquered a vast area.

I.e. no argument for making the patch to improve gameplay design or conserve or improve balance, but only the argument that the pop bonus does not apply to mauryas and persians because their population size or reigned area coincided with their environment rather than being properties of the civ?
What about the argument that the game just represents, conveys, portraits the historic circumstances and puts the player into the same position that the civ was in?

then give them a discount on training time (already the case for Persians), unit costs, barracks, population per house, farming bonus, whatever

Firstly, then why doesn't the patch do that?
Secondly, this is an argument about the means to portray a civ characteristic, whereas the other part of the sentence said that its just not actually relatable / specific to these civs.

To me it seems the criteria to give a civ a relative pop bonus is to do it when that civ historically had much more population too.
For that matter I suppose more than these two civs should receive that bonus?
I suppose one would need to grab statistics for that.
Were Mauryas and Persians the greatest empires at the 0ad timeframe? Were there larger ones? How large was Rome at that time? Perhaps Rome already has so many bonuses that they were decided to not get that as well.
One could look into the commit history, trac, forums and IRC history to grab logged thoughts of the authors that gave them these bonuses in order do distinguish them from the speculation (but it's not unlikely that it was something was an experiment, or WIP, only for demonstrative purposes only or whatever not good).

everyone built walls, the Iberians not more frequently or better than anyone else.

I suppose that discussion has different grounds / offtopic.

Mauryan city walls cost wood instead of stone and are consequently weaker (Indians were not known for their stone architecture, contrary to Persians and Greeks) are in my opinion good civilization bonuses

(Mauryan city walls are not weaker than Briton walls, that bonus seems nice conceptually but the wood cost seems too strong currently, the reward/cost ratio)

Making Mauryan infantry cheaper but with less armour would be another one (Indians were not known for wearing body armour, whereas Roman infantry was known for their chainmail).

Maybe that could be done as well, they should probably have less HP or armour then too (+ having fun balancing that).

But still doesn't explain to me why pop bonus for a historically pop rich civ was wrong?
The benefit of having any civ with a pop bonus is that it distinguishes civs in more ways in a very noticeable and unique way than if no civ had that bonus, and it one can give that bonus to the historically most reasonable civs as well while weighing against balancing impact.

But still doesn't explain to me why pop bonus for a historically pop rich civ was wrong?

Again, the Persians and Mauryas had large population not because they were Iranian or Indian, but simply because they conquered a vast area which already had a large population. Their population density was not any higher than that of Greeks or Celts or other contemperous sedentary peoples practising agriculture.

What about the argument that the game just represents, conveys, portraits the historic circumstances and puts the player into the same position that the civ was in?

0 A.D. doesn't. Mauryas do not start with e.g. 100× as much territory as other civs in 0 A.D. to represent their large empires.
Likewise, the Persians controlled hundreds of cities, the Spartans had none in their homeland; that doesn't mean Persians were great city builders (they conquered older states) or that Sparta shouldn't be able to advance to the city phase.

Were Mauryas and Persians the greatest empires at the 0ad timeframe? Were there larger ones? How large was Rome at that time?

The Persian (Achaemenid) Empire was significantly larger than any earlier empire, uniting areas that had never been united before, and consequently had an enormous population, estimates range from 10 to 40 million around 500 BC. The Mauryas emerged only after Alexander had conquered the Persian Empire, at least partially because of the power vacuum Alexander left in Northern India; because Alexander's empire splintered after his death, the Mauryas were clearly the largest in Hellenistic times, reaching 50 to 60 million around 250 BC. When the Mauryas were already in decline, Han China emerged; they had a population of 50 to 60 million around 1 BC. Rome controlled a population of perhaps ten thousand around 500 BC and 50 to 60 million around 1 BC, because at that point they had conquered the entire Mediterranean. Nonetheless, all these populous empires are the consequence of conquest, not of anything intrinsically special to their civilizations. (Likewise, players tend to have small populations at game start and high at the end, provided they're not defeated by their enemies.)

One could look into the commit history, trac, forums and IRC history to grab logged thoughts of the authors that gave them these bonuses in order do distinguish them from the speculation (but it's not unlikely that it was something was an experiment, or WIP, only for demonstrative purposes only or whatever not good).

These population bonuses were introduced with rP12748 (13 October 2012). As far as I can see they've never been critically evaluated since, even though 0 A.D. isn't the same it was seven years ago. E.g. Spartan citizen soldiers no longer promote to Elite rank after one kill any more (the stated reason for introducing that pop cap penalty); currently Sparta is rather similar to Athens and Macedon (and the Theban civ has been removed).

I suppose that discussion has different grounds / offtopic.

Indeed. Let's focus this discussion on only the pop cap bonuses.

I don't agree with this patch.