Timeline
by Geoff GanderThe first empire of Mogreth probably arose in BC 5500, as per the ancient Cynidicea Gazetteer (original timeline excerpt below - note that some of this may be dated now):
BC 5500: Akhor, sole survivor of a Carnifex colony on Brun, and a sorcerer of renown, makes his way to the swampy region that will become Ylaruam, in the southeastern corner of that continent. He befriends local primitive lizard men, who revere him as a god.
BC 5200: By this time Akhor has brought all lizard men in the region under his control, and he has educated the most intelligent ones in the ways of Carnifex magic. His Empire of Mogreth covers the whole valley, and subjugates local Neathar and Oltec tribes. These tribes are put to work in the mines and in the fields, supplying the material wealth of the empire, while the lizard man over-class rests in relative luxury. Akhor, due to his long lifespan and great powers, is named Akhor-K’ha (Akhor the Mighty) by his subjects.
BC 5100: A peace treaty is concluded with local dragons, in which Mogreth will remain unmolested so long as the dragons are not bothered. There have as yet been no conflicts, but Akhor wishes to avoid them at all cost. Mogreth at this time has no dealings with any cultures beyond the mountain ranges that constitute its borders, and none who enter the empire from outside ever leave.
BC 5000: Akhor and his disciples implore upon the Outer Beings to present a sign that They are pleased with local developments. Zargon is sent as the Herald of the Outer Beings, and he obeys Akhor, and advises him in matters of faith.
BC 4500: Akhor attains immortality in the Sphere of Entropy, unknowingly guided by Thanatos. Even upon attaining immortality, Akhor still believes that the Outer Beings are sponsoring him. A council of high priests and sorcerers takes over, as Akhor ventures to the Outer Planes in search of a way to free the Outer Beings.
BC 4000: A civil war in the Empire ensues. Mogreth society has become increasingly stratified, as human slaves increasingly resent their lot, and the lizard man sorcerers resent the power of the priests. The slaves revolt, and many cities are destroyed. The sorcerers and priests begin fighting each other.
BC 3900: The sorcerers, believing that Zargon is the source of the priests' power, devise a means, using now-lost Carnifex magics, to seal him away in a pocket dimension. They attack the main temple, slay the priests, and seal away Zargon. Imbuing five electrum disks, engraved with sigils, with the powers of the spell, they then hide these "seals" throughout Mogreth, in the hopes that no one will find them, and discover the means to free Zargon. Unfortunately, the Carnifex spell is too powerful for a mere magical item to contain; the seals will last only a few thousand years.
BC 3800: The empire of Mogreth is destroyed by a combined assault of Oltecs, Thonian colonists, and dwarves. It had long been an obstacle to free travel in the area, and they feared its powers. This is not before some of Mogreth’s greatest sorcerers use their powers to attain lichdom, or build great sanctuaries underground. Many lizard men go into hiding along with their leaders, while others flee south, towards what is now Ierendi and Minrothad.
BC 3300: Several settlements are founded along the coast of what was once Mogreth by Thonian colonists. The local lizard men who remain are enslaved.
As a postscript, I would add that the lost Carnifex colony in Brun that Akhor fled was likely an offshoot of Y'hog (not the realm of Orzhekh, where Hrugesh-K'ha lived). I would probably reduce the extent of Mogreth to coincide with my map (save the larger realm for the second empire), as the pre-GRoF climate for the region was quite cold due to the KW's more northerly location. The coasts might have been habitable (moreso with magic).
As far as the map goes, I realise that the Ylari region would have been lush, but that was the only map I was able to find online at work (Pandius is blocked, otherwise I'd have used James Mishler's map of Nithia). Much of Mogreth's population was concentrated on the now-sunken swampy delta/peninsula.
Now, the second empire of Mogreth arose in the post-GRoF chaos. The lizard men had scores to settle, and some of the surviving liches stirred from their underground hideouts to take quiet control over the region. By BC 2900, much of the old territory had been taken, and the local humans would have been enslaved or driven out. The second empire reached its height around BC 2500 (controlling the area in blue as well), but by BC 2000 conflicts with Taymor were taking their toll (although Taymor never conquered Mogreth). There may have been a brief resurgence after the Taymoran collapse, but the rise of Nithia soon drove the remaining lizard men to the hills and mountain valleys.
In my own work, I have the remnants of Mogreth persist after the fall of Nithia (perhaps they, influenced by Thanatos, played a role in the fall of Nithia). One Mogrethian wizard, Senkhor-K'ha, threatened the Salonikos region until he was defeated in AC 86 (I wrote a little dungeon crawl about this - an element of it is in the Vaults - see the piece on Temthrull), but after that there would have been no incursions or activity. It's entirely possible that one or two small valleys in the Altan Tepes may contain isolated refuges, but DMs can determine whether anything lives there anymore...
I just remembered - if you want to use fan-created material, then the following could be in play:
The marginal lands of the western coasts of what is now Frisland, as well as Limn, are occupied by three jarldoms - Ostheim, Gronborg, and Markland - all of which were settled between 600-800 BC by Antalian settlers from Ystmarhavn. These realms sold their services to the Alphatians from time to time in their own battles with the indigenous Yannifey, but by BC 48 they would be conquered by the growing Alphatian Empire.
Further north, on the island now known as Qeodhar, is the Jarldom of Ystmarhavn, a powerful realm of fearless seafarers who ranged all over the north, from Brun to Skothar. The realm was at its height in BC 500, and would outlast Nithia by many centuries before succumbing to Alphatia.