The Titans and the Ordering
Dating unknown
No one knows for sure how the universe began. Some think that it began with a huge explosion, sending the worlds in the Great Dark. Others think that it was created by one single power. Though this is unclear, it is certain that a race called the Titans arose. The came from all corners of the universe. They moved from world to world and gave it their own shape and life. The Titans were ruled by the Pantheon. An elite part of the race. Their goal was to create order where chaos had been, to safeguard the new worlds. They had to protect it from the Twisted Nether, an ethereal dimension, connecting the worlds in the universe and inhabited by countless Demons, who wanted to destroy all life. The Titans were pure-hearted and couldn't be corrupted by those evil forces. The Pantheon sought out their best warrior to defend the worlds and try to eradicate all evil. His name was Sargeras.

The Burning Legion
Dating unknown
Sargeras fought the Demon that entered the physical world for countless millenia. Over time, Sargeras encountered two powerful Demonic races: The Eredar, devilish sorcerers who consumed countless worlds. Though Sargeras easily beat them, he slipped into a depression, because he could not imagine the corrupting evil within them. Sargeras locked them in a far corner of the Nether.
Sargeras became more confused and depressed and he had to face the Nathrezim, an order of vampiric Dreadlords. Their powers had set nations up against each other and turning the inhabitants into shadows. Their corrupting abilities affected Sargeras as well, and Sargeras started losing his faith in the Titans' vision on order. Sargeras left the Titans. The Pantheon let him go, but never fore saw what he would do.
Sargeras' mind went even more insane and thought that the failure of creation was the fault of the Titans. He went to undo all that was done by the Titans. His form morphed into a flaming being. He released the Eredar and Nathrezim. Those Demons, still inferior, were now his servants. Sargeras chose two of the mightiest Eredars as his champions to lead the Burning Legion, as he called it. Kil'Jaeden the Deceiver was ought to corrupt the darkest races in the universe. Archimonde the Defiler was chosen to lead Sargeras army to battle against those who tried to oppose them.
Kil'Jaeden first enslaved the Dreadlords and they became his agents for corrupting other races. Tichondrius the Darkener was the first to fall under the Eredar's control.
Archimonde called up his own agents: the Pitlords under command of Mannoroth.
Now the army was amassed, Sargeras launched it in the Great Dark to destroy countless worlds.

The Ordering of Azeroth
Dating unknown
Then the Titans came to a world which the inhabitants would call Azeroth later. On this little world they met Elemental begins. Those worshipped the Old Gods and vowed to drive the Titans back. Still, they were no match for the awesome Titans, which drove their Old Gods back into the center of the world. The elements went back as well, now missing the power of their gods. The world was peaceful now and they forged the world into one big continent. They created new races to help them and carry on their work. When they were done they made a lake at the center of the continent, empowered with magical energies. They called it the Well of Eternity. This Well would make life grow and evolve on the world. All kinds of creatures came to exist. The Titans called the continent Kalimdor: Land of Eternal Starlight.
Before the Titans left again, they empowered the greatest race with magical powers to watch over the new world. The Pantheon gave five Dragons their powers: Alexstrasza the Life-Binder, Malygos the Spell-Weaver, Ysera the Dreamer, Nozdormu the Timeless, and Neltharion the Earth-Warder. Now they're called the Aspects.

Well of Eternity
About 10.000 B.I.
A nocturnal humanoid tribe was drawn to the Well by its life-giving powers. They built their homes around it and the Well affected them over time, making them wise, strong and nearly immortal They called themselves Kaldorei, what meant Children of the Stars in their own language. This race, that later would be known as night Elves, worshipped the moon goddess, Elune, from who they thought was in the magical lake. Early priests studied the Well's possibilities while the lands of Kalimdor were explored by others of their tribe. No race caused them to stop, except for the ancient Dragons, which tried to safeguard all lands. Somehow they saw themselves as the protectors of the world, and the Elves decided it was the best to leave them alone.
Over time the curiosity of the Kaldorei made them meet powerful beings, like Cenarius. He was a demi-god of the ancient world. He started to like the Kaldorei and taught them about the natural world.
As ages passed, their territory and culture expanded. They were led by the beautiful queen Azshara. She built an enormous palace on the shores of the Well and lived in there with her closest followers, called the Quel'dorei, the High-borne. They saw themselves as superior to the other Kaldorei. The masses secretly hated this reclusive group, except for their queen. The Quel'dorei studied the Well's potentials even further and over time they learned how to manipulate the energies. This way they found the first primitive magic and they devoted themselves to it. Though Cenarius and other night Elf scholars warned them for danger, the Quel'dorei kept on practicing their magical abilities. As they used magic more they became more apart from the other Kaldorei. Furion Stormrage, a young scholar, began to suspect a terrible power was corrupting the Quel'Dorei and Azshara.

The Sundering of Worlds
About 10.000 B.I.
The usage of the Well's power sent out signals across the Great Dark Beyond. Sargeras, which had gained titles like Great Enemy of all Life and Ravager of Worlds, felt these signals. As he found out about the immense powers, he decided to claim that world and it's powers for himself as well. Azshara and her followers were corrupted totally and agreed to open a portal for the Burning Legion. They worshipped Sargeras as their new god. They opened a portal in the Well of Eternity and Sargeras sent his army trough and so the invasion began. The Legion laid siege on the Kaldorei cities and swarmed out over the lands leaving only death. Furion, and his brother Illidan, one of the Quel'Dorei went to Cenarius to raise a fighting force. They were accompanied by Tyrande Whisperwind, who was the priestess of Elune. The brothers both secretly loved Tyrande, but she loved only Furion. Illidan's heart was pained by this, but his addiction to magic hurt even more. She was the only thing that kept him going while he struggled, because he wanted to tap energies again from the Well, from which he had come to depend on.
When they found Cenarius, he helped to get the aid of ancient Dragons, led by Alexstrasza. Cenarius called upon the Spirits of the Forests to come up with a army of ancient trees. Though this army was very strong, Furion realized it wouldn't be enough to stop the Burning Legion.
While the battle continued, Azshara waited for Sargeras arrival. While his shadow came closer to the surface Azshara gathered her priests, because only their combined powers could make a portal for Sargeras. Furion knew that the Well was the origin of the Evil that had entered their world and he wished it to be destroyed. The addicted Illidan left his brother, because he knew that the Well's destruction would make him unable ever to use magic again. He went to warn the Quel'Dorei.
While Furion and his companions attack the summoning High-born, most died, because of Illidan's betrayal. Tyrande tried to attack the queen from behind, but she was caught off guard by the guards men. Furion, seeing his love fall, went in a rage and ended Azshara's life.
Meanwhile Illidan appeared at the Well's shores and put some of the water in special vials.
Because of the battle between Furion and Azshara the spell became chaotic and the vortex exploded and changed the world forever.

The Demon Soul
About 10.000 B.I.
With this first big Demonic invasion, the Aspects too had to take actions to drive them back into the Twisted Nether. As they appeared to be failing, Neltharion came with the idea to create an artifact with their powers, to make it of great power, great enough to get rid of the Demons. A golden disk was made and all of the Aspects put more than half of their powers in it. At least, they thought: Neltharion never added his power, but the Demon Soul, as it was named, was still powerful enough. After the defeat of the Demons, his treachery was found. Neltharion had implanted great parts of adamantium, one of the strongest metals on Azeroth, in his body to make his imperishable armor even stronger. The Demon Soul had the power to control all Aspects, except for Neltharion, because his power wasn't added. The other Aspects were no match for him anymore, because they sacrificed most of their power. So they cast a spell on the Demon Soul, in order to make the Earth-Warder unable to use it. Then they threw it in the depths of the earth. Neltharion never faced the other Aspects again and named himself Deathwing, the name known to mortals. The Elves called him Xaxas, what means Dark One in their language. Nozdormu retreated to his realm collecting items over time, but never doing much to the outer world. Malygos went totally insane and retreated as well to his cavern. Alexstrasza and Ysera were the only active Aspects now, but didn't appear that much in the open again.

After the Great Sundering
Estimation: during few thousand years following the Great Sunder
The earth was ripped apart and most lands of Kalimdor sunk beneath the seas. As result of this, a giant and chaotic storm appeared at the place where once the Well of Eternity had been. It is now known as the Maelstrom. Almost eighty percent of the lands had sunk, leaving only a few continents surrounding the seas of the Maelstrom.
Tyrande, Furion and Cenarius, who wondrously survived the explosion, went with crude rafts to the nearest lands and agreed to build up the new world together. Many of the Quel'dorei had perished during the battle and the events after it, but many survived as well. Furion still didn't trust them, but without the Well, they had no power and let them live. The Night Elves came to their holy mountain Hyjal and went to the summit. There they found and peaceful lake, but the discovered it was fouled, by magic. Illidan had survived as well, and used his collected waters to convert this lake to a new Well of Eternity. Furion hunted his brother down and with the help of the demi-god Cenarius, he locked Illidan in the depths of the earth forever. They left the lake for what is was, afraid of greater catastrophe than before. Furion vowed they would never use its powers again and the Night Elves started to learn the art of druidism to heal the lands that remained.
After they worked for years to rebuild the lands and establish and empire in the new forests, the surviving Dragons emerged again and heard about the new Well. They foresaw a new invasion from the Legion and made a pact with the Arch-druid Furion to keep the Well safe. Alexstrasza the Life-Binder threw one acorn in the Well, and because of its magic a giant tree sprung up from the grounds. The World Tree was named Nosdrassil, what meant Crown of Heavens in the language of the Night Elves. It was the symbol of the pact. Nozdormu the Timeless, enchanted the Tree to make sure that as long as the tree lived, the Elves wouldn't age nor die from disease. Ysera the Dreamer linked Nosdrassil to her own ethereal dimension known as the Emerald Dream. All druids, including Furion, would sleep forever, or until they were needed once again. The druids selflessly agreed.
As the years passed the race of the Night Elfs grew strong again and expanded over the forest which were now called Ashenvale. Creatures from before the Sundering reappeared, like Fulborgs and Quilboars. But the High-Borne grew restless again and their hunger for magic became bigger. Dath'Remar began to mock the druids in public. He called them because, because they refused to use magic, something that was rightfully theirs. The druids warned that any use of magic would be punished by death. But Dath'Remar and his follows tried to convince them by unleashing a magical storm on Ashenvale. Because the druids couldn't just slaughter so many of their own kind, they decided to exile the High-Borne. They were set on ships to sail over the seas and beyond the Maelstrom. Later they would find a continent Called Lordaeron and establish their own empire called Quel'Thalas. They were known as the High Elves from that point.

The Sentinels
Estimation: during few decennia following the Great Sunder
After the departure of the Quel'Dorei, the night Elves focussed on the lands around them again. The druids felt their time for sleep came again. Tyrande, now the First Priestess of Elune, asked Furion not to go, but he wouldn't quit his task to go to his slumber in Ysera's realm.
Tyrande was now left alone and was burdened with the task to protect Ashenvale. She assembled a fighting force from her night Elf sisters and called themselves the Sentinels.
They still had other allies to call for, in times of need. Cenarius remained close to Mount Hyjal in the Moonglades and his children, the Keepers of the Grove and the Dryads helped the Elves watching over the lands.
Tyrande felt that alone without Furion, though her task kept her busy, worrying about a possible other invasion from the Burning Legion.

Order of Tirisfal
Dating unknown
The survivors of the Kaldorei wanted to make sure, that nothing like it would ever happen again. The Order of Tirisfal came to existence, by some of these Elves. What Tirisfal was or is, is unknown. First they kept every knowledge hidden from the other races, but the Humans, which were enslaved by the Kaldorei but had survived, started to use magic as well and later started unknowingly to opening the door for Sargeras step by step. Then the Kaldorei came out of hiding and told the first mages what happened so long ago. The mages realized that even if they stop using magic, others would. This way the Order continued to exist as a secret group among the most powerful mages. One of those mages would be chosen Guardian of the Tirisfalen. He or she would be given the greatest power and would keep the Demons from entering this world. The problem was that now the doorway was everywhere, not focused in one well.
Over time, personal and political interests came among the Order's mages, and the Guardian became more a servant that a keeper.

Aegwynn
About 800 B.I.
Coming later with The Last Guardian

The Shadow Council
Around 30/40 B.I.
In his youth, Gul'dan learned the magics of Shamanism and grew much stronger than his tutors. Even stronger than Ner'Zhul the greatest of them. Gul'dan's thirst for power was not limited by the devotion to his people, the Orcs, like the other shamans were. Once he met a creature of huge power, during his explorations in the Twisted Nether. This Demonlord Kil'jaeden became his tutor and taught the shaman much about what was beyond the world of Draenor, on which they were slaughtering the inhabitants. Gul'dan came in touch with the spirits of the dead and knew then that if he could bind them to his will, they were a powerful weapon. Gul'dan became the greatest Warlock of his time, but when Draenor was conquered totally, the started started to battle eachother, because there was nothing left to do.
Gul'dan gathered the Warlocks which seemed to be willing to rise above the clan quarreling. Gul'dan taught them about the dead and channeling with the Twisted Nether. The weak didn't survive and the strongest formed the Shadow Council. From that time a secret group of Warlocks, which had great influence on the clan politics. Still Kil'jaeden was the one that lead us all to becoming the secret heart of the Horde.
Gul'dan started with teaching a new way of magics: necromancy. He taught new Warlocks about life's and death's mysteries. These Necrolytes eventually gained the power the raise and control the dead.

The Invasion of Azeroth
Around 0 B.I.
Something contacted the other Warlocks in the Council, but Gul'dan wasn't contacted by this presence. Even Kil'jaeden felt and feared this power. Gul'dan himself went into the Twisted Nether and moved around there for an unknown time. Until the Presence found him. The Presence identified himself as Medivh and was indeed of great power, but not emotionless like Kil'jaeden acted. This Medivh made contact with Gul'dan's mind and learned a lot about the Orcs and their magics. Gul'dan only realized that he wanted to use this power for himself. After it, Gul'dan sought counsel of Kil'jaeden but the Demonlord didn't answer. When Medivh appeared to me again he showed me a world... as a target for the Horde's attack. After a long time, in which Medivh appeared to have vanished, a rift suddenly appeared. After a while it was big enough to send an Orc through. After some scouting the world on the other side appeared to be the one Medivh showed in the vision. The Shadow Council enlarged to rift to create a portal. The scouts reported that the inhabitant were a weak race called Humans. Two chieftains, Cho'gall and Killrogg Deadeye were sent out to overthrow the Humans. The forces of the Horde went through the Portal and charged the keep nearby: Stormwind.
Expecting a weak resistance, the Orcs charged uncautiously and were set back by the soldiers of the Humans. The surviving Orcs fled back into the Black Morass surrounding the Dark Portal. Killrogg and Cho'gall blamed eachother for their humiliating defeat, and the Shadow Council sought a solution. They found it: Blackhand the Destroyer, the chieftain of the Blackrock Clan. He was honored by most Orcs and with Gul'dan's help he quickly became War Chief of the Horde. Blackhand was corrupted and blackmailed by Gul'dan for his own gain...
Medivh appeared to Gul'dan again, and ordered to take over Azeroth and make him leader of the Orcs. Gul'dan refused: the planet would be theirs, also without Medivh. Then Medivh showed him an ancient tomb. He called it the Tomb of Sargeras. Sargeras was the tutor of Kil'jaeden. Kil'jaeden had told Gul'dan that that tomb was the key to unlimited power. Medivh promised the Warlock the location of this tomb in exchange for the Horde killing his enemies. And so the Horde prepared to make war against the kingdom of Azeroth.

The First War
Just few months after The Invasion
Gerona, a half-Orc assassin of Gul'dan, killed King Llane of Azeroth and the Horde razed the lands. Despite this Gul'dan's plan was stopped aggressively. A small group of Human warriors attacked Medivh's tower and killed him. Gul'dan tried to get the location of Sargeras Tomb before he died, but he was too late and was in Medivh's mind at the time of his death. This caused Gul'dan a massive psychic backlash and he fell into a catatonic state.
For a long time he slept as if dead with the Warlocks guarding him. When he woke up again, things had changed a lot: without Gul'dan as his counselor Blackhand was assassinated by Ogrim Doomhammer, the strongest and most trusted generals of the Horde. He had risen as the new War Chief.