Flavius Josephus, The Wars of the Jews
William Whiston, A.M., Ed.

[419] And as he transmitted to eternity his family and friends, so did he not neglect a memorial for himself, but built a fortress upon a mountain towards Arabia, and named it from himself, Herodium ¹ and he called that hill that was of the shape of a woman's breast, and was sixty furlongs distant from Jerusalem, by the same name. He also bestowed much curious art upon it, with great ambition, and built round towers all about the top of it, and filled up the remaining space with the most costly palaces round about, insomuch that not only the sight of the inner apartments was splendid, but great wealth was laid out on the outward walls, and partitions, and roofs also. Besides this, he brought a mighty quantity of water from a great distance, and at vast charges, and raised an ascent to it of two hundred steps of the whitest marble, for the hill was itself moderately high, and entirely factitious. He also built other palaces about the roots of the hill, sufficient to receive the furniture that was put into them, with his friends also, insomuch that, on account of its containing all necessaries, the fortress might seem to be a city, but, by the bounds it had, a palace only.