Symes and a Geometric horse

Source: Schinousa archive
courtesy of Dr Christos Tsirogiannis

Dr Christos Tsirogiannis has identified a geometric horse from the Symes archive. The horse is due to be auctioned at 'The Shape of Beauty: Sculpture from the Collection of Howard and Saretta Barnet' at Sotheby's New York on 14 May 2018 (lot 4). 

Sotheby's provide a history of the horse and do acknowledge the link with Symes:

• Münzen und Medaillen AG, Basel, May 6, 1967, lot 2 
• Robin Symes, London, very probably acquired at the above auction 
• Howard and Saretta Barnet, New York, acquired from the above on November 16, 1973

When did the horse leave Greece? Who consigned it to the sale in Basel? Did the Barnets acquire other material from Symes?