FileFront Forums - The greatest battle in warhammer history...

i thought this was the greatest battle... if the sm lost the space marines and ig would not be in w40k
The Siege of the Imperial Palace

The Landing on Terra

The siege began with an orbital bombardment by the Warmaster, the prelude to invasion. Although the Loyalist fleets and defences fought back, they, like the Loyalists soldiers on the surface, were too few, and were mown down without mercy.
After days of bombardment, the Traitor Space Marines landed on the surface in drop pods, taking the two spaceports nearest the Imperial Palace. Five Traitor Legions participated, combining with Traitor forces on the surface. Despite the brave efforts of the Loyalists, The Eternity Wall and the Lion's Gate Spaceports fell within hours. Dark Chaos cultists made their invocations, calling down the Greater Daemons of Chaos onto Terran soil.
With the spaceports secured, Horus's troops landed en masse, and the hulking transports carried thousands of troops each. The transports' immense size made them prime targets for Terra's defence lasers. Although many landing ships were destroyed, many more landed on the surface, disgorging yet more soldiers, tanks and Titans to add to the besiegers' strength. They met stiff resistance, the Imperial defenders knowing that the survival of their homeworld, their Emperor, and the entirety of the human race rested on their shoulders.

The Siege

The besiegers forced the defenders back to the walls of the Imperial Palace, where thousands died slowing the assault. Angron came forth and demanded the Loyalists surrender, saying that they were cut off, outnumbered, and defended a ruler unworthy of their loyalty. Many would have surrendered to Angron had it not been for the Primarch Sanguinius, winged leader of the Blood Angels. The two Primarchs gazed at each other, probably communicating telepathically. Eventually Angron withdrew, telling his forces there would be no surrender.
The siege began in earnest. Three times the forces of Chaos scaled the walls, and three times were hurled back by Sanguinius and his Blood Angels. Outside the palace walls, forces led by Jaghatai Khan, Primarch of the White Scars unsuccessfully tried to draw the bulk of the besieger's army away from the Palace. Soon the outnumbered defenders were pushed back into the maze of corridors and bulwarks within the Palace walls. Frustrated with his army's slow progress, Horus ordered his Titans to demolish entire sections of the wall. Despite grievous losses, the Titans gouged open breaches, which the Traitors flooded through.
Jaghatai Khan decided on a change of plan. Rather than assaulting the almost-invincible flanks of the besiegers' army, Khan redirected his White Scars and the surviving Loyalist Tank Divisions to Lion's Gate Spaceport. At dawn Jaghatai's lightning raid caught the Traitor garrison by surprise, and reclaimed the spaceport. The Khan ordered his troops to to reactivate the defense lasers and form a defensive permiter to hold their newly reconquered territory. Khan's troops repelled several bloody counter-attacks from the Traitors, and began firing on Horus's unprotected dropships. The Khan's plan worked: the flow of men and machines to the Palace had been halved at one stroke.
Inside the Palace, the defenders had been forced back to the Eternity Gate, the sole point of entry into the Imperial Palace. The Blood Angels and Imperial Fists tried to hold back the attacking Chaos troops, while the remaining Imperials made it through the Gate. Soon the mighty Bloodthirster Ka'bandah came forth and bellowed out a challenge to Sanguinius. The daemon hurled itself at the Angel of Baal, barely allowing him time to parry the daemon's strikes. The two took to the air, trading blows and battle cries high above the heads of the two forces. Already fatigued from the siege, Sanguinius was cast down by the daemon, pulverising the concrete below upon impact.
Yet the Blood Angels' Primarch was not beaten. Sanguinius cleared his head, forced himself back to his feet, and once again took to the sky. The Angel seized the gloating daemon, holding it by the right ankle and arm. The Primarch hefted the creature high and broke its back over his knee, then hurled the daemon's vast carcass back at the beseigers. The Traitor armies wailed in despair as the last Imperials retreated into the Palace. The Eternity Gate was closed.

The Endgame

The Emperor and Horus in the endgame of the Heresy, with the Primarch Sanguinius lying dead at Horus's feet. For a better, more updated picture, another depiction of the stand-off can be found here

The siege lasted 55 days. Both sides knew the defeat of the Imperium was near. Sensing this, Horus prepared to teleport to the surface to lead his forces in person. Before this could happen, the Word Bearers' First Chaplain Erebus broke the news to Horus: the Ultramarines and Space Wolves Legions were nearing Terra; and the Dark Angels were only a short distance behind.
At that moment, Horus realised his gamble had failed. Weeks of further conflict would be needed to break the defenders; the Emperor's reinforcements would arrive in hours. It was then Horus gave the most fateful order of the Heresy. He ordered that the shields protecting his flagship, The Vengeful Spirit, be dropped immediately. Horus gambled that this would draw the Emperor from the surface and into a duel.
The Emperor rose to the challenge, leading his Adeptus Custodes, the Primarch Sanguinius, Rogal Dorn, and several companies of Imperial Fists and Blood Angels Veterans in the assault. Horus used his powers to scatter the Emperor's force throughout the massive warship. Each fought a series of battles aboard the corrupted ship, attempting to link up with their comrades and confront Horus.
It was Sanguinius who reached Horus first. The Warmaster attempted to turn the Blood Angel Primarch to Chaos. When Sanguinius refused, Horus attacked. Wounded from his many battles on Terra, Sanguinius was no match for Horus, now at the peak of his daemonic power. Horus strangled the Angel of Baal with ease.
When the Emperor entered, he saw the corpse of Sanguinius lying at Horus's feet. Horus called the Emperor foolish for refusing the power that the gods of Chaos offered, and timid for not taming them to his will. If the Emperor would kneel before him, then he would spare his life. The Emperor knew well the trap that had snared Horus. He told him that he was the deluded servant of Chaos, not the master. Snarling, Horus hurled bolts of Daemonic lightning at the Emperor, but the Emperor nullified them. The die was cast. Each god-like being knew that the fate of humanity hung in the balance.
The Emperor and Horus engaged one another, battling physically and psychically. Though the Emperor's psychic gifts and martial skills were unequalled, he found himself unwilling to summon his full strength against his son. The Emperor suffered grievous wounds at Horus's hands, and after score of thrusts, parries and counter-thrusts between runesword and lightning claw, Horus sliced open the Emperor's chest armour, then opened his jugular and severed the tendons in his right wrist, disarming the Emperor. A psychic blast seared the flesh from the Emperor's face, bursting an eye. After tearing the Emperor's right arm from its socket, Horus raised his father high over his head, and broke his back over his knee.
At that moment, a lone Adeptus Custode entered the bridge. Horus showed him the Emperor's broken form and laughed at the Custode. He roared and charged the Warmaster. He was flayed alive by a glancing psychic blast from Horus. [In previous editions of the tale, an Imperial Fist Terminator attacks Horus; in older versions, the doomed man is an Imperial Guardsman named Ollanious Pious.]
The casual brutality of the act galvanised the Emperor. Realising at last that his favoured son was truly lost to the corruption of Chaos, the Emperor finally mustered his full power, and unleashed a lance of pure Warp energy that pierced the gloating Horus's defenses. The Chaos Gods themselves recoiled in terror, withdrawing from their pawn. Just before Horus died, he looked his father in the eye, shedding a single tear, begging his father to finish him for his betrayal. The Emperor saw regret in his fallen son's eyes. The Emperor also knew that Chaos could attempt to possess Horus again, and that he would not be there to halt him if they did. Driving all compassion from his mind, the Emperor destroyed Horus utterly, his essence burned from existence.
Horus's death sent a psychic shockwave surging across the Solar System, casting the Chaos daemons back into the Warp, spreading mass panic in seconds. It became clear to the forces of Chaos that their leader had been defeated. A berserk fury had encompassed the Blood Angels at the moment of their Primarch's death, and they were surging forth to scatter the attackers. Retreat turned to rout, and rout turned to bloodbath; thousands upon thousands of Traitor Marines and Titans fell attempting to flee. The ground before the Sanctum Imperialis ran red with the blood of traitors and heretics.
Meanwhile, Rogal Dorn finally found his way to the ship's bridge, only to discover his fallen brother, Sanguinus, and the Emperor, now at the verge of death. It was then that the Emperor whispered instructions to Dorn, urging the Imperial Fists Primarch to take him to the Golden Throne. The surviving Loyalists teleported back to the Imperial Dungeons. Here Malcador the Sigilite, who had briefly taken the Emperor's place on the Throne, thus keeping the warp-gate beyond it closed, collapsed to dust as he was removed and the Emperor put in his place.
The Emperor spoke his final words to his followers. He urged them to continue the fight to free humanity from the forces of Chaos and ignorance that continued to assail it. And then the master of mankind spoke no more, his body entombed within the life-support mechanisms of the Golden Throne, his spirit caught between the warp and in a crippled body for millennia. The Imperium of Man survived, but would become the bastion of repression and brutality the Emperor had fought against. It would also offer humanity its best hope for survival in an uncaring universe.