Ancient Roman CarnelianEXTREMELY RARE image of the sea God Poseidon riding a KETOS sea monster Vs Andromeda

Ancient Roman Carnelian Gemstone with an image of the sea God Poseidon (Neptun) holding his sceptre (probably trident) riding Ketos (Cetus) . Ketos (Cetus) is a sea monster (sea snake) sent from Poseidon to against Cassiopeia and her daughter Andromeda and eat them to protect the Nereides in their beuty contest which grew into a feud. This kind of image appears EXTREMELY RARE especially on gemstones. Influenced exclusively from the Ancient Greek and later Roman Mythology and with a great importance from this point of view! Broken, but almost the whole image is visable. Material: Carnelian Date: 1st. Century BC.
-3rd. Century AD Size: 1,3cm. Item No. O56 Purchased by the current owner in 2011 in Austria, Wien from Collector fair. Collected Since: 1980's. Previous owners history: Old Austrian Private Collection. The Seller can prove that the lot was obtained legally , provenance statement seen by Catawiki. Important information. The seller guarantees that he is entitled to ship this lot. The seller will take care that any necessary permits will be arranged. The seller will inform the buyer about this if this takes more than a few days.