I had a few questions about the second founding. These will probably be addressed in the upcoming supplement "honour the chapter", but there is probably enough fluff out there to get the ball rolling already.

First, is there an estimate about how many second founding chapters there were? I ask that because the second founding must have been the absolute nadir of space marine numbers. Before that, there were no chapters, only legions, which numbered in the thousands, one source stated that the Ultramarines were about 250,000 strong, but they were the largest of the legions by far.

The second founding was essentially the splitting of the Legions after the horus heresy. Already, half of the legions were decared traitors and chased into the eye of terror. Losses on both sides must have been staggering. The Ultramarines in one source stated that they split into about 23 or 24 chapters, but that they were the largest source of new chapters. It also implies losses of 90% which is large, but I guess possible given the brutal war that the Horus Heresy was. The Space wolves were able to sire 1 chapter, indicating about 2,000 space wolves by the end of the heresy, The Imperial fists broke up into the Crimson Fists and the Black Templars. The salamanders were so weakened that the sources strongly hint they did not create any successor chapters. One count of the recorded Second founding chapters was 34, which indicates that there were about 43,000 Space marines left after the Horus Heresy.. That is kinda cool, because they still went off to reconquer the imperium which just goes to show how awesome Space Marines are to begin with.

Which brings me to the next point…

Why are the founding chapters considered so special? Since the second founding chapters were essentially the same as their parent chapters only with a new name and a different colour on their armour. Why are the Ultramarines considered the greatest of all chapters when all of their successors were essentially Ultramarines under a different name. I do not think that the First founding chapters got the pick of the litter and let the other chapters get their weaker marines. I can understand subsequent foundings because the gene seed and tradition started to get a bit fuzzy. But wouldnt a Ultra marine successor be expected to perform just as well as an actual Ultramarine? Food for though.

Do recall that even from the start, some Chapters did not care about the Codex. From the Imperial Fists, we got them and the Crimson Fists, both Codex-strong at 1000 Marines, and pretty much everyone who said "screw the Codex" went into the Black Templars, which explains how there are probably over 10,000 of them in the present day.

In the same vein, Space Wolves said "screw the Codex" and maintained a possibly larger force than exists today, but certainly larger than the 1000-strong Codex Chapter.

To estimate about Second Founding: The Imperial Fists Legion split into three. Blood Angels into like…3 or 4 if I recall. Dark Angels split into like…4 or 5. Raven Guard split once or twice, forming the Raptors and maybe another. I don't think the White Scars or Salamanders split at all (perhaps they did but can't remember anything saying they did). Ultramarines split into 25 or so, but recall they ONLY fought around Ultramar, they weren't involved in actions like Istvaan V like the Salamanders/Raven Guard/Iron Hands or the Siege of Terra like the Imperial Fists, White Scars (who suffered greatly taking the spaceports) and Blood Angels. Similar to the Dark Angels who were pretty much just dealing with their own traitors and thus had more left over than those at Terra. Also recall that we have maybe 100-150 or so named SM Chapters, where there are around 1000 in canon, leaving PLENTY of leeway to invent more.

The key with your second question is they are NOT the same. They may have started out the same…then they went to settle on and control different worlds with different base cultures, they had different experiences, grew in a different way from different stimuli even if they come from the same genetic stock. And it's been 10,000 years. Cultural changes happen in the greater Imperium over that time period, why not in the Chapters?

Also Ultramarines are greatest "because Matt Ward" and because "hey we didn't do a whole lot over here but now we outnumber you all so do what Gulliman says for some reason even though he has no moral superiority, having not been at Terra," which wraps around to "because Matt Ward." =P

According to Lexicanum, there are 38 confirmed Second Founding Chapters, making 47 total at the end of the Heresy, what with the First Founding Chapters. Plus, it's a common theory that a lot of older chapters with unconfirmed founding dates could be from the Second Founding. So we're really not sure how many Loyalist Astartes there were at the end of the Heresy. There were only 700 Salamanders, and the Raven Guard and Iron Hands suffered similarly heavy casualties, but I can't say for sure if that means there were significantly less than 47,000 Loyalists after the Siege of Terra. Could easily have been more, though.

As to why the Ultramarines get more love than the Silver Skulls, White Consuls, Genesis, Novamarines, or any of their other successors… Well, for many of them, they were led by their Primarchs at their inception. Not the Iron Hands or the Blood Angels, of course, and I can't speak for the Dark Angels, but the other six had their Primarchs. Also, the intelligence- or lack thereof- in the Imperium has to be taken into account. Your average hiver isn't going to know that much about the division of the Legions into Chapters, so when he hears legends of, say, the White Scars riding into battle during the Siege of Terra and then they hear about the White Scars and the Storm Lords serving together a system over, they're going to connect more with those figures of legend than with this other group that didn't do diddly against the Arch-Traitor.

Yeah, at a guess I'd say the UMs had the most, followed closely by the Dark Angels.

Why? Neither was at the Siege of Terra or the Slaughter in Istvaan.

The Smurfs got hit hard by the Word Bearers though, possibly losing up to 70% of their strength. Think on this. Yes, they PROBABLY had around 250,000 or so at the highest estimates (I think it was said to be 225,000 in the Battle for Calth book)… but even at that high number, 70 percent losses means…And further battles after that. My guess is between 9 and 20 successors. Erring to low end because that's the only way any of the numbers would make sense.

The Dark Angels were doing some nasty fighting of their own, and had the civil war. And were probably in the 125,000 range, conservatively, before the end… but then lost about half to their own little civil war and quarter that again AT LEAST for losses taken by survivors. 5-10 successors and them. Again, seems right. PROBABLY the second most.

The Fists had 3 successors. With the Caveat the Templars may not have been nearly so… low in numbers as 1000 men. This was deliberate.

Blood Angels I'd guess had a similar amount to the Fists by the end. 3-5 is my guess by the enforcement of the Codex.

White Scars I think we can safely put at similar to the above. Siege of Terra participants. As a digression, they seem to be the Chapter that GW seems to 'get' the least. And is still trying to figure out their story. Note they've STILL not shown up in the Horus Heresy novels at all, except maybe the barest mention here and there. I can't think of anyone else in the series who has had less coverage except maybe Vulkan - but even he's been mentioned more. (Sanguinus as well, but he'll be in a book soon, there's nothing White Scars even announced yet for the Heresy series). It's likely they are waiting for someone to truly 'get' them. MAkes me sad I didn't manage to get my novel pitch even close to done, because as a Historian of the Mongols (Did my MA in Mongol Empire Warfare) I probably would be a darn good candidate! As much as Andy Hoare (I think that's who it is) has done a couple White Scar books, they don't seem very… right. They don't seem to get the mobile nature of the Chapter.

Space Wolves flipped the bird to Guilliman and didn't bother with a true successor right away. That said, they were one of the smaller chapters by this point to begin with. But may have had 10-20,000 men even without splitting.

The Iron Hands had at least one I believe. But I'm not positive. Either way, I doubt it was more than one or two.

Salamanders we don't know had any.

Raven Guard also had at least one - the Raptors. I'd guess they had 1-3 more on top of that. At most though. Mainly due to Corax' aggressive attempts to rebuild. Failure or not in the grand scheme, the traditional stuff must have had at least some effect.

So at first, the Smurfs weren't 70 percent or more of the Successors. BUT..,. their gene seed meant future foundings were primarily from them so things shifted.

It's also interesting to realize that the Modern Imperium may well have more Space Marines than it did during the Crusade. Especially if the 1000 number often bandied is the low end estimate. (The math has been done elsewhere, and it looks like Heresy Era numbers were anywhere from 1 million to 1.6 million or so right before the Heresy) But even then, the Imperium probably has more Marines now than it did at the end of the Heresy, and more Loyalists by far than Traitors ever existed.

This comes close to the 38 number bandied. Especially leaving some 'special snowflake' room for Loyalists from the Traitor Legions, which we know existed.

EDIT: And I just looked it up. I was DARN close with my estimates! http://wh40k.lexicanum.com/wiki/Second_Founding#.T-_cjbUs_Ak