This watch is a Tiffany & Company 18k solid gold case and the s/n is consistent with a Patek. I have been advised by a Facebook watch page that the movement is probably a Koehn but, the S/n 111357 is not found in any of my Koehn searches. I am trying to get an extract from Patek, but having a dog of a time getting it to process my credit card. Please bear in mind the serial number of 111357 (i think it has validity) It is marked on case and movement as well. I believe the S/n date range is 1895-1900. Any help would be appreciated.