Moscow City Clay 1661-1662 "The two-headed eagle with the RO letters."

The earliest Moscow marks are the two-headed eagle of various designs, in shields of different shapes, sometimes with a date expressed initially in Slavic letters, later in Arabic numerals. The mark is in the form of a triangle, with the letters "P" and "O" depicted next to the eagle heads. (1661-1662) Shape: inverted triangle.