Ammianus Marcellinus Res Gestae 17.4.15

[15] After this there remained only the raising, which it was thought could be accomplished only with great difficulty, perhaps not at all. But it was done in the following manner: to tall beams which were brought and raised on end (so that you would see a very grove of derricks) were fastened long and heavy ropes in the likeness of a manifold web hiding the sky with their excessive numbers. To these was attached that veritable mountain engraved over with written characters, and it was gradually drawn up on high through the empty air, and after hanging for a long time, while many thousand men turned wheels ¹ resembling millstones, it was finally placed in the middle of the circus ² and capped by a bronze globe gleaming with gold-leaf; this was immediately struck by a bolt of the divine fire and therefore removed and replaced by a bronze figure of a torch, likewise overlaid with gold-foil and glowing like a mass of flame.