Thanks for the information. Yes, I have considered that. I posted a photo of this button on a Turkish Military Collector's site and was led to a web site that showed an identical button used on a WWI Turkish uniform. No information was given on it's backmark though. Short of running across a uniform with the same button and backmark, I don't suppose there will be anyway to identify it for sure. My button came from a London collector, so it makes me lean toward a European origin.