This word is probably a corrup- tion of Genoese, and it was applied to a coin of very inferior metal brought to Eng- land by traders from Genoa.
Spenser, Faerie Queene (iii. 7. 58), says: " Because I would not give her many a Jane. "
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)