Nothing much is known of the Khajiit in between their settlement of the deserts and forests of Elsweyr and their foundation of a common confederacy. Prior to 2E309, Elsweyr was almost continuously mired in internal conflict and strife between its tribal factions. Due to its tribal strife, it was incapable of presenting a common force to external enemies, and, in the words of the Pocket Guide to The Empire, "the nearly constant insurrection and tribal warfare among the catmen rarely troubled the stage of history." What is known is that Khajiit have some knowledge of the events at Red Mountain and the war of the First Council, as they have their own name for the eruption at Vvardenfell Mountain, "Sun's Death."
Elsweyr established central government in 2E309, under the guidance of Keirgo of Anequina and Eshita of Pellitine. There is some uncertainty as to the nature of the agreement between the two Khajiit leaders, with the Pocket Guide stating that it was a combining of kingdoms, the Imperial Library's timeline stating that it was a uniting of tribes, and an email from developer Ted Peterson stating that it was an alliance. In any case, the name 'Elsweyr' arose from an old Khajiiti proverb that went along the lines of "perfect society is always elsewhere." The resultant state caused a great deal of discord amongst the members of the former feudal aristocracy, who, feeling betrayed, chose to rise up in arms against the united state. Keirgo fruitlessly petitioned the Empire of Cyrodiil for aid and was met with failure, for the Cyrodiilic Empire was experiencing its own internal issues. The former capital of Anequia, Ne Quin-al, fell to the rebels. A ceasefire was achieved when the normally nonpartisan spiritual leader Mane Rid-T'har-ri'Datta stepped in to broker talks. A lasting peace ensued, as the tribes and the urbanized elite established terms whereby control of Elsweyr shifted according to the phases of the moons Masser and Secunda. The PGE writes that the two parties to the deal experience only nominal control of Elsweyr, and that true power lies in the Mane, whose government is "secretive" and "despotic." The PGE doesn't seem to care much about the events between 2E309 and its own publishing date, 2E864, stating that "Elsweyr has withdrew itself into a secrecy that has scarcely been breached in five hundred years."
Potentate Versidue-Shaie, a Tsaeci of Akavir, who began the Second Era of Tamrielic history by assassinating the last of the Reman dynasty of Emperors and took up the throne of Cyrodiil, established his palace in the Elsweyr kingdom of Senechal. He was murdered there in 2E340 by assassins, members of the Morag Tong, a religious order from Morrowind.
A seized portion of Elsweyr was made the assemblage site of the Dwemer artifact known as the Numidium. Popular rumor suggests that the Numidium was part of a gift from Lord Vivec to Emperor Tiber Septim in exchange for the lenient treaty incorporating Morrowind into the Cyrodiilic Empire. The land was taken by a contingent of the Emperor's elite guard, the Blades, and forcibly cleared of its native Khajiit population. Upon that land the Halls of the Colossus were built. Imperial Engineers under the Battlemage Zurin Arctus then assembled the machine. "Official Imperial records merely state that Arctus sacrificed his heart to be infused into a gem called Mantella, and later to be implanted into the Numidium to make it fully operational." Native Khajiiti inhabitants record that a Dragon Break occurred during the assemblage process, which led to continuing health issues for generations onward. An opposing account, contained in the Arcturian Heresy, states that the soul contained in the Mantella belonged to the Underking previously known as King Wulfharth of Skyrim. An anonymous letter sent to the player character in the early stages of TES: Daggerfall writes that the Numidium was "a thousand foot tall automaton, a golem or an atronach of sorts" The Numidium enabled Tiber Septim to destroy his last opponent, the Aldmeri Dominion, finish his conquest of Tamriel in the year 2E896, and commence the Third Era. The official record also records that the Numidium was used again to destroy the unallied royal families of Cyrodiil, giving Tiber Septim absolute authority over issues of succession. The Numidium was lost in a battle with Arctus, wherein both were destroyed, and the Numidium was scattered across Tamriel. The Empire seems to have deliberately obfuscated the story surrounding the Numidium, trying to place the location of the Halls of the Colossus in Cyrodiil, and creating an alternate history for the halls, wherein they were built by giants. The player character visits the Halls in TES: Arena, in pursuit of the various pieces of the Staff of Chaos, the main quest of the game. Upon arriving, Ria Silmane speaks to the player.
Following the tumultuous history of the Numidium, which only touches on Elsweyr briefly, surviving literature records no event in Elsweyr until 3E394, when the Five Year War began. The war began following an event the Khajiit call the "Slaughter of Torval." The Khajiit claim that over a thousand Khajiti citizens were killed by an invading Bosmeri force from Valenwood without provocation, while the Bosmer claim that the attack was in retaliation for the disruption in trade resultant from Khajiti raids on Valenwood's wood caravans. The war ended in 3E399, with a Khajiti victory, following tactical and strategic moves by Khajiit tribesmen that were seen as impressive both by foreign commentators and the tribesmen themselves.
The herb and alchemical ingredient Nightshade is native to the Elsweyr, and is reputed to be quite poisonous. Khajiit cherish it and attribute magical powers to it, hiding it in "their armor to increase their abilities to skulk, hide and become invisible." The plant is also to be found in Western Cyrodiil, surrounding Skingrad, but also in lesser quantities around Bravil in the Nibenay Basin and Cheydinhal in the Northeast. In the game TES: Oblivion, Nightshade, properly processed, damages health and luck, burdens, and fortifies magicka. As no further effects are registered, it could be presumed that the Khajiit habit remains a bit of superstition. It's also notable that moon sugar (a fictional drug found in TES universe) grows here.