This Hipparchia. syriaca lives in South East Europe and has only limited overlap, if any, with the extremely similar Hipparchia alcyone, who lives in Central East Europe.
Much more problematic is Hipparchia fagi, that shares almost the entire range of Hipparchia syriaca.
However, according to some authors, on most of the islands of Greece, including Rhodes, only Hipparchia syriaca occur, so I am pretty confident my butterfly at Rhodes is Hipparchia syriaca. 

Petaloúdes Valley, Rhodes, Greece, 26 September 2012