Rare, engraved, Winchester First Model 1866 'Flatside' Saddle Ring Carbine that was manufactured in 1866. The carbine has the distinctive First Model features which include: (1) flat loading port cover secured by two screws, (2) two upper tang screws, (3) 'Flatside' receiver with no flare at the junction with the forearm and (4) Henry style receiver profile with distinct 'drop' ahead of the hammer. A brass sling ring secured by a iron staple is located on the left side of the receiver. The uncrowned barrel has the early style threaded magazine cap with no screw, front barrel band with integral front sight blade and two-leaf carbine rear sight. The stock and forearm are straight grain American walnut. The stock has the Henry style crescent brass buttplate with hinged brass trap utilized on early Model 1866 carbines. The top of the barrel is roll-stamped: "HENRY'S-PATENT. OCT. 16. 1860/KING'S-PATENT-MARCH 29. 1866" in two lines between the lower barrel band and the rear sight. The serial number, "13187" is stamped on the left side of the lower receiver tang. The upper tang inlet on the stock and the inside of the buttplate are serial numbered "13404". The brass (gunmetal) receiver is silver plated and the buttplate is gold plated. The barrel, magazine, barrel bands, hammer, lever and trigger were blued or color case-hardened. The top and sides of the receiver upper tang and cartridge elevator are extensively engraved with deluxe scrollwork and intricate borders. The left side of the receiver features a large Mexican Eagle and Serpent motif surrounded by tight scrollwork on a punch-dot background while the right side of the receiver is covered with tight scrollwork. A crown has been added to the eagle's head and "F. Maximiliano/Emperador de Mejico" is period inscribed in two lines along the upper sides of the receiver. The crown and inscription were engraved by a different and less skilled hand than the scrollwork and eagle motif. This carbine is accompanied by 17-page letter by firearms expert R.L. Wilson. The Wilson letter states that this carbine was engraved by L.D. Nimschke either for Winchester or Schuyler, Hartley & Graham and is "The First Engraved Winchester". He further states that this carbine could have been a sample directed by Oliver Winchester to the Emperor Maximilian of Mexico (1832-1867). The Wilson letter does not address the distinct difference in the quality of the engraving in the inscription and the addition of the crown to the eagle head. Wilson's letter states that this carbine was pictured on page 43 of his book THE BOOK OF WINCHESTER ENGRAVING (1976) but was not included in the 1989 edition of WINCHESTER ENGRAVING because no photograph was available. The Wilson letter notes the mis-matched serial numbers on the stock and buttplate and states that mis-matched serial numbers are not unusual due to the pressure for the factory to produce the first Winchester rifles and carbines. Also included with this carbine are several articles on the life and short reign of Emperor Maximilian.