Not long after that fateful encounter in the planes, Alassra Shentrantra arrived in Aglarond, southwest of Rashemen, due west of Thay where dwell the Red Wizards, longtime enemies of Alassra's one-time guardians and—not at all coincidentally—home to Lailomun's mentor. Without revealing her name—any of her names—the Sixth-of-the-Seven offered herself as an apprentice to Ilione, sister of Halacar, King of Aglarond at that time, though Ilione knew no magic that Alassra hadn't known for at least a century.
As the years passed, Alassra buried her love for Lailomun and raised it up again in the simple folk of Aglarond. The vengeance Mystra had forbidden became the just defense of her new homeland. Time and time again, Alassra directed her fury into the land of Thay and against the corrupt Red Wizards who rule there. At Ilione's suggestion, King Halacar dubbed the nameless apprentice, the Simbul, a meaningless title, so far as I have been able to determine, but one well-respected in Aglarond where it became synonymous with a tall, silver-haired woman, with lightning eyes and a temper to match.
Emboldened by his sister's fierce apprentice, King Halacar launched Aglarond's small army against the Red Wizards, but, for all her magic, the Simbul was not yet a warrior and certainly not a competent army commander. The Aglarondans barely avoided a rout. The people lost faith in their king; the king lost faith in his sister and the Simbul. For a year the very air of Aglarond was rank with anarchy and treason, until the king died, poisoned, it was said, and probably by Thayan hands—though no one looked hard for the culprits.
Ilione succeeded her brother on Aglarond's Verdigris Throne. She restored order and righteousness throughout her kingdom, as is recorded in many other chronicles. She built Aglarond's first navy and rebuilt its army, but kept it home. Throughout Ilione's sixty-year reign, her apprentice, the Simbul, oversaw Aglarond's borders and—sometimes with the army's aid but more often alone—kept them secure from Thayan incursion.
Before she died, Queen Ilione named the Simbul as her heir. By then, of course, the Aglarondans knew the Simbul was no ordinary human woman, no ordinary wizard. No noble family nor merchant faction was foolish enough to object to the Simbul's coronation in the Year of the Watching Cold.
For seven years now, Alassra Shentrantra has ruled as the Simbul. She is at best respected, more generally feared, and only rarely loved by those around her. She keeps the Red Wizards out of Aglarond, and for that she commands her realm's undivided loyalty.
Notes for an examination, Written by Mehgrin, apprentice at Candlekeep, placed, by accident, in Cirian's Concise History and filed with it (The day was very dreary, and the headache very bad)
Zandilar: a goddess, maybe, called into being in the Yuirwood a long time ago by humans who lived in crude lakeside huts and hunted with stone-tipped spears. The only depictions of her from that time show her either naked and dancing or running with animals—usually horses—while hunters throw spears. (Does this mean that there were two Zandilars?)
When the Tel'Quessir came to Faerun, a tribe of the Sy-Tel'Quessir took the Yuirwood for their own. They were stronger and smarter than the humans; they had their own gods, who were stronger and smarter than gods like Zandilar. The humans disappeared from the Yuirwood after the Sy- Tel'Quessir arrived, but their Seldarine gods absorbed Zandilar and the other old human gods instead of driving them out.
According to the Sy-Tel'Quessir, there was only one Zandilar and she was always dancing. They knew her as the goddess of physical passion and romance, and when they depicted her, they depicted her with a cat, not a horse, because cats are like that. Probably she was a popular goddess, but not an important one, and the other Tel'Quessir never adopted her or any of the other gods the Sy-Tel'Quessir worshiped in the Yuirwood.
Once the Sy-Tel'Quessir were in the Yuirwood, nothing changed, for a very long time. Then the Yuirwood Sy-Tel'Quessir got careless and got tangled in wars with goblin-kind and the drow. They drew their gods into the wars with them, and even though they won the wars and kept the Yuirwood, they lost, too, because they and their gods had done bad things in order to win.
So the Sy-Tel'Quessir of the Yuirwood began to forget things. They began to die. When humans came back to the Yuirwood, there weren't many Yuir elves left, and they'd forgotten most everything that had ever been important to them, including their gods. Other elves remembered the Seldarine, but only the Yuir elves had ever known about Zandilar, Relkath, Magnar and the other old human gods.