Here is a fairly rare type
Constantine I
A.D. 312- 313
22x23mm 4.3gm
CONSTANTINVS P F AVG; laureate & cuirassed bust right.
FELICITAS AVGG NN; Roma, helmeted, seated left, holding branch in right hand and globe in left; ✶ in left field.
In ex. PLN
RIC VI London 246
Some London coins celebrating the defeat of Maxentius (http://www.lateromanbronzecoinforum.com/index.php/topic,491.msg1353.html#msg1353)