Long before the Undead Invasion, when Leth Nurae was a center for magical study, a respected High Elf mage by the name of Silas Lucertae made great magical discoveries and accrued considerable political power.
One of his discoveries grew to be an obsession for him, and the power of the magic he was summoning began to change him. One of these changes was a new-found interest in his political influence. His arrogance and hunger for power grew ever greater until he killed another elf in a fit of anger.
Tried for his crime, he rose up, attacking all around him with his considerable power, and establishing himself as ruler of Leth Nurae. He shut the city away, and became a tyrant to its inhabitants until the arrival of a cloaked stranger who gathered Leth Nurae's surviving mages and led them against Lucertae.
Lucertae was defeated, and all but one of the city's mages killed. The stranger who had led them vanished.
The history of Silas Lucertae is revealed in Morgan's Tale.