Hi, Harris!

As Harris could probably say better than I could, the Greek modes are not all named after Greek tribes. The Lydians and the Phrygians were non-Greek nations/tribes in Anatolia. (Their languages were related to Hittite, if memory serves.) Croesus, who rich people are as rich as, was a king of Lydia.

More relying on my memory: these modes are not the ancient Greek modes. They're church modes (as Bob Bolton implied) that were named after the ancient Greek modes.

A jazz musician on a list I read says that the Locrian mode is popular in contemporary jazz. Those guys LIKE diminished fifths. (Actually, I sometimes do too.) They even mutate standards into Locrian, which hardly seems fair.

"The Campbells are Coming" is in the Phrygian mode (at least in the sense that if played on the white keys, it ends on E).