Second Sundering

The Second Sundering, also known as the Sundering of Toril and Abeir, was a great catastrophic event in the recent history of the worlds of Abeir and Toril, that took place during the decade of the 1480s DR.
When Ao the Overgod destroyed the Tablets of Fate at the conclusion of the Time of Troubles, he instigated the Era of Upheaval. The Tablets defined the laws of Realmspace and kept it relatively stable. Without them, chaos ensued and the worlds of Abeir and Toril, separated many thousands of years ago, slowly started to overlap. The Spellplague drastically sped up this process.
The Second Sundering started with Ao's decision to recreate the Tablets of Fate, and to separate the worlds of Abeir and Toril once more. The deities were unsure of what this would do to them and their power, and made efforts using their most powerful servants to prepare for that event.
The Second Sundering was somehow connected to the First Sundering that took place around −17,600 DR, when an elven High Magic ritual went both forward and backward in time to create Evermeet; and with a prehistoric cataclysm known as The Tearfall, that took place in −31,000 DR.
The Second Sundering brought significant changes to how the deities approached mortals. Many gods became "quieter" than before, causing the emergence of new priesthoods in an attempt to explain the different divine behavior in the post-Sundering world.