Yesterday I exchanged several e-mails with my German friend Francisco Welter-Schultes concerning a snail that was once (and only once) recorded from Turkey. While attempting to figure out where exactly in Turkey this snail may have been found, we discussed some old German papers and touched upon a multitude of other subjects, including Kleinarmenien ("Little Armenia"), the Turkish town of Amasya and Rums.
To the Turks of Turkey a Greek is a Rum (pronounced "room"). Although most Turks wouldn't know it, Rum actually means "Roman"1. The reason why the origin of Rum may be obscure to them is probably because it has been in use for many, many centuries.
Sevan Nişanyan, in his etymological dictionary of Turkish2, gives the origin of Rum as the Greek romiós. A much older etymology shedding more light on the origin of the word was given by a Thomas Smith in the following 1683 article from the Royal Society's Philosophical Transactions.
In his 1st sentence Smith is referring to Constantinople and "the Empire" is the Byzantine Empire. "The continent of Thrace", on the other hand, is the name given to the northwest corner of the present day Turkey (Trakya in Turkish) and the adjacent area in Greece across the border. The Ottomans referred to that area also as Rumeli ("the Land of the Rums"). In a nutshell, and if my understanding is correct, what Smith was saying is that after the Roman Empire collapsed, the Byzantine Empire centered around Constantinople was seen as the former's continuation. Hence, the Greeks became "Romans".
Smith's spelling of Rum as Vrum may have been due to his misunderstanding of its pronunciation. His Vrumler Padisha must have been Rumların Padişahı or "the Padişah of the Rums". Padişah (pronounced padishah and originally from Persian), the equivalent of "emperor", was the title of the Ottoman sultans.
1The present day Turkish word roman (originally from the French romance) means "novel"; the word for a Roman is Romalı ("a person of Rome"), while a Rumen is a Romanian. But a Romanian could also be called a Romanyalı. Finally, the Turks call Greece Yunanistan. So, a Greek is also a Yunan(lı). Yes, it could get complicated.
2 Sevan Nişanyan. 2003. Sözlerin Soyağacı.