H. P. Lovecraft 
The Doom that Came to Sarnath [EPUB ebook] 

More than 10, 000 years ago a race of shepherd people colonized the banks of the river Ai in a land called Mnar. Craving more land, a group of these hardy people migrated to the shores of a lonely and vast lake at the heart of Mnar, founding the metropolis of Sarnath. But the settlers were not alone.