British Celts, Tincommius or Tincomarus. AV quarter stater. 11 mm, 1.18 g. ca. 25-1 BC. 

C-A above and beneath TINC on rectangular tablet.
Winged head of Medusa facing, a pair of snakes knotted below 
the chin, a snake descending on each side of the face.

Van Arsdell 378-1; Seaby 77; Rudd 1076; BMC 811-826.

With permission of Roma Numismatics auction XII, Lot 1, Sept. 2016