The elves were perfect beings. Long-lived, hearty, wise, and skilled at magic. Her creations, the spiders, were looked down on and generally maligned by the other gods and their creations, despite the beautiful web-work they created.
And so she decided to steal her brother's elves. Things began small. Bands of elves were corrupted, made into dark elves, known as the drow, and turned on their brethren. Skirmishes broke out across the continent of Lorius. Eventually, it spilled over into the rest of the world. This time was known as the Elf Wars. Lolth had corrupted a large majority of the elves, and only a few remained to fight. However, most of the other gods sided with Corellon against Lolth, and all the races of the world all fought against her and her monstrous creations. Those gods who did not side with Corellon Larethian remained neutral, and Lolth was all alone.
The wars raged for nearly a hundred years, ending when Corellon bound Lolth and all her brood in the icy wastelands in the south. While the powerful magics used in the war had dramatically changed its landscape, not all of its consequences were bad. The isolation that had separated the different races for so long had ended, and a new age of peace came upon the land. This was nearly three thousand years ago.