German octagonal gold and rock crystal watch Circa 1630-1640

Gold, enamel and rock crystal verge watch by Johann Possdorfer
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A very fine and rare German gold, enamel and rock crystal octagonal verge pocket watch, circa 1630-1640.
Hinged octagonal gilt brass, partly blued full plate chain fusée movement, verge escapement, plain steel two-armed balance without spring, small-footed irregular oval foliate pierced and engraved cock secured by a pin. Signature on the back plate of the movement: J. Possdorffer / Dresden. Dial decorated with enamel flowers and leaves in colours of blue, green, and orange against a gold background, white enamel centre with Roman radial hours, and gold single-hand. Gold and rock crystal case.
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Dimensions: 32 x 22 mm
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Signed: J. Possdorffer / Dresden
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Watchmaker: Johann Possdorfer (German, active in Prague and Dresden, recorded 1620–24)
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The association of Possdorffer with the superb Swiss clockmaker Jobst Bürgi (1552–1632) during a period when both worked in Prague for Prince Karl I of Liechtenstein (1569–1627) undoubtedly provided the opportunity for the transmission of the technical secrets of Bürgi’s cross-beat escapement from Prague to Dresden. There, Possdorffer made a watch with a cross-beat escapement, which probably made it one of the most accurate portable timekeepers until the invention of the balance spring. The watch is now in the Grünes Gewölbe in Dresden. The Metropolitan Museum’s watch has an ordinary verge escapement. With an enamelled dial that only registers hours and half hours, it is remarkable more for its tiny size than for its accuracy. The rock crystal cover is a replacement.