Double Antoninianus of Tactius, Antioch Mint

Double Antoninianus (X/I ratio of silver) of Tacitus, (23mm, 3.51g). Antioch Mint. RIC V Tacitus 21. IMP CM CL TACITVS AVG. // CLEMENTIA TEMP H//XI. 4th Officiana, 3rd em. Scarce issue.

The Double Antoninianus was an experimental denomination in a vain attempt to rebase the currency to a specific silver content denoted on the coin itself. The reverse shows "X I" meaning 1 of 10 parts silver or 10% silver. Clearly this attempted failed as they did not mint many. Due to Gresham's Law, Bad money drives out the good, so these would have been taken out of circulation while lower purity Antoninianus were spent in the economy.