The War of the Heavens

The Third Age is also known as the War of the Heavens. Its beginning was marked by the confrontation of Tempus by his three dark siblings. When Tempus raised his sword to strike Lozitar he came down with such might that it spawned Heironeous Tyr as a champion for him. Chemosh Kelemvor struck back and destroyed Tempus' shield, from the shattered shield Paladine arose. With Chemosh vulnerable after the recent attack, and Tempus' hand freed up he swung out with a thunderous punch and the force generated Trithereon Torm. Noticing that they were now outnumbered and apparently outmatched Shara Takhisis ripped the shadows from Paladine and Trithereon to create Sargonnas the Fury and Bane. The battle ensued for a very long time destroying several material planes.
While the War of the Heavens wreaked havoc across the planes Aureon Celestian focused on his meditation. The power he generated leaked from him into the dirt and was soaked up by the roots of the tree. The tree became sentient and was known as Beory Chislev, from it sprung three fruits, growing into St. Cuthbert, Zivilyn, and Gilean Oghma. Aureon was able to stabilize the Sun and left St. Cuthbert to continue holding the plane in balance as the War of the Heavens raged on, while Aureon himself went to create more stars to light up the skies even when darkness has its grip on the realms.
After all of the other material planes were destroyed and the War of the Heavens came to the Prime Material plane, they had noticed that there was an aura preventing them from manifesting their whole powers. Nonetheless the gods found themselves charging at one another. Through the dust Lozitar was able to spot Tempus and ran him through with his blade. Tempus fell to his knees, Lozitar withdrew is sword and proceeded to stab at Tempus to inflict pain. Tempus fell to the ground whispering to the dirt, followed by a long exhale. The exhale rose visibly and became corporeal, becoming Talonus Morgab. The sword that stuck down Tempus fell from the hands of Lozitar and arose as Bhaal. The fighting stopped as the others realized that one of them had been slain. The dust settled and they noticed that Hextor had appeared, created by the fray itself. Noting that this plane had somehow made them mortal, the gods left the plane vowed to refrain from physically returning.
Maintaining the balance of the last material plane was very taxing on St. Cuthbert. He used all of his power to ensure that the other gods could not destroy this plane when he was here, but the all out brawl of the other gods was enough to force him to go into stasis, becoming a stone image of himself, eternally meditating.