Last of the Semis (1/2 As) coins struck under Hadrian. In the Roman Republic around 300 BC these were heavy cast coins with a weight of 160 grammes, rapidly dropping to 20 grammes in 200 BC and under 10 grammes in 100 BC. Bought this one for $8 last week which was listed as a Limes Falsum.
Trajan Decius had a semis over a century later. https://www.cngcoins.com/Coin.aspx?CoinID=22346 Nice ones are not common.