
Originally Posted by
Edax
What the wiki says:
First Umbral Calamity
The First Umbral Calamity or Calamity of Wind marked the beginning of modern history on Hydaelyn, heralding the First Umbral Era. While scholars once debated on the elemental aspect of this Calamity, the coming of the Sixth Umbral Era allowed scholars to determine that the First Umbral Calamity was one of wind─possibly in the form of terrible hurricanes, tempests, or tornadoes.
The tale of Good King Moggle Mog XII seems to allude to the events of this Calamity, telling of a time when the skies that were once home to all moogles became embroiled in a battle between the gods. Good King Moggle Mog XII helped his brethren flee to the safety of the lands beneath the clouds, though he was forced to remain behind. The moogles of Moghome have also spoken of a wind-driven disaster previous to the first five calamities, seemingly corroborating the events of the legend.
The First Umbral Calamity was responsible for Rejoining the Fifth shard to the Source.
Second Umbral Calamity
The Second Umbral Calamity or Calamity of Lightning came on the heels of the First Astral Era, an age where mankind learned to forge stone tools and established settlements and towns, which grew into kingdoms that soon went to war, each seeking to expand their domain. To forge their tools and weapons, mountains were gutted and skies blackened.
Nature was despoiled for countless years until the balance tipped. Volcanoes spewed black smoke that covered the skies and plunged the realm into eternal darkness. Bolts of lightning rained down from the skies for a full year and a day, forcing mankind to seek shelter underground in caverns. These caves became breeding grounds for pestilence and plague. In their desperation, the people prayed for salvation, giving birth to the earliest forms of magical incantations.
The Second Umbral Calamity was responsible for Rejoining the Twelfth shard to the Source.
Third Umbral Calamity
The Third Umbral Calamity or Calamity of Fire resulted from the dramatic shift to religious worship in the realm that followed the decline of kingdoms and discovery of magic. These churches became as corrupt and powerful as the kings that preceded them, and their desire for control began an age of holy wars, witch hunts, and genocide.
Theologians believe that the gods grew weary of mankind's hubris and decided to humble them. The sun grew large and an intense heat parched the land. Wildfires spread, reducing fields and forests to wastelands, the people stricken with famine. Fossil evidence found in the desert Grand Wake in Thanalan suggests that the deserts that now make up southern Eorzea were once a lush grassland lost in the fires of this Calamity.
The Third Umbral Calamity was responsible for Rejoining the Second shard to the Source.