Res Gestae

And because sycophants, after their fashion, kept puffing up Constantius and endlessly dinning it into his ears that, whereas Octavianus Augustus had brought over two obelisks from the city of Heliopolis in Egypt, one of which was set up in the Circus Maximus, the other in the Campus Martius, as for this one recently brought in, he neither ventured to meddle with it nor move it, overawed by the difficulties caused by its size-let me inform those who do not know it that that early emperor, after bringing over several obelisks, passed by this one and left it untouched because it was consecrated as a special gift to the Sun God, and because being placed in the sacred part of his sumptuous temple, which might not be profaned, there it towered aloft like the peak of the world.