Lot
2373 
Special Delivery, 1916, 10¢ pale ultramarine, exceptionally well centered within large margins, used with 2¢ carmine (425), tied by bold strikes of "Rome N.Y. Nov 4, 1916" duplex on small blue piece, Very Fine. Scott No. E10 Estimate $200 - 300.
This is the earliest known use of E10..