Akrian Dein was an Elven missionary who traveled to Albaria in 60AV. The missionaries were captured and brought before Emperor Alaurek, and all were executed except for Dein, who was imprisoned for a decade. In 70 AV he was again brought before the Emperor, and this time was released, but banished to western Albaria. There he wandered until 73 AV, when Elder Tleirek took him in as a tutor for his children. From there he wrote the book, "Legacy of Lanival" and also brought knowledge of the Thirteen to the Kaldar. However, by 159 AV his teachings caused the Emperor Caedus's daughter to convert to the Thirteen. The Emperor sends an army to the West to apprehend Dein, who surrenders in order to protect the Kaldar. He is then sacrificed in 161 AV to Xosiurion after the Gnomic Prophets and High Priest declare him a heretic. In the years after his death, the Gorbesh began removing all traces of his existence and teachings.
By 208 AV, hostilities rose to the point where Empreror Tarion declares war on the Kaldar. While full-scale war does not come to pass, as the Council of High Priests reminds the Emperor of Sievox's Decree, a hundred years of heightened tensions ensues. In 300 AV, as border conflicts were rising between the Kaldar and Gorbesh, word at last reached Albaria of the fall of the Seven-Star Empire. Hostilities declined at this point as efforts became focused on invading the Kermorian provinces.
Akrian Dein is known to be the original missionary that attempted to bring worship of the Kermorian Thirteen to Albaria and the Gorbesh. His teachings have largely been morphed since his original concepts were introduced and an indeterminate percentage of Kaldar that remain within Albaria now follow his teachings despite the initial attempts to wipe out his teaching. A much larger number of Kaldar in Kermoria simply follow the Kermorian Pantheon and view Akrian's teachings to be pointless and redundant while living in Kermoria. The Gorbesh do not follow Akrian's teachings at all.
The original concepts introduced by Akrian can be found here.