you are correct on that
"Although extraordinary valor was displayed by the entire corps of the Spartans and Thespians, yet the bravest of all was declared the Spartan Dienekes. It is said that on the eve of battle, he was told by a native of Trachis that the Persian archers were so numerous that, when they fired their volleys, the mass of arrows blocked out the sun. Dienekes, however, quite undaunted by this prospect, remarked with a laugh, "Good. Then we'lkl have our battle in the shade."
Quote from Herodotus that is in the begining of the book