You may have overheard some of your more bookish friends attempting to one-up your certainly basic understanding of music theory by referring to the Greek modes. But here’s an interesting fact: the Ionian, Dorian, Phrygian, etc. modes are not actually the modes originally used by the Greeks.
The history of how exactly they have developed into variations of our familiar Western 12-tone scale is muddied by many writings from Europe between the 6th and 9th century. Furthermore, half of the modes might have been plagal, meaning they were completed by the addition of lower notes instead of higher ones (in which case the mode is called authentic), like the Gregorian modes. Either way, the modes would better be called “medieval” or “church” modes, as they were predominantly used in the time of Pope Gregory I, in the Roman Catholic church during the 10th-13th centuries.
So, the next time some hipster asks you what Greek mode the new Iron and Wine single is in, first answer Ionian or Aeolian, and then sock it to them.