In 293 Diocletian instituted the Tetrarchy: government of the geographically divided Empire by four interacting rulers - two Augusti assisted by two subordinate Caesars which each Augustus would personally select. Diocletian, Augustus of the east, selected Galerius Maximian as his Caesar and Maximian Herculius, Augustus of the west, selected Constantius as his Caesar. The first assignment given Constantius by Maximian was to remove Carausius, the usurper Augustus of secessionist Britain, and restore that former possession to the Empire. Constantius thereupon beseiged and captured Boulogne and then wrested coastal Gaul from Carausius. Constantius now set about planning the invasion, occupation and restoration of secessionist Britain to the Empire. One of the first orders of business for Constantius was to insure that a supply of reformed aes coinage - now the commonplace legal tender of the Roman Empire - was available for use not only by his occupying force, but also by the British civilian populace. To that end Constantius established a Continental Mint (exact location unknown although some French sources list it as Boulogne), manned by Lugdunese workers, to produce this invasion coinage - unmarked (i.e. without a mint mark) folles issued in the names of Diocletian & Maximian Herculius as Augustus and Constantius & Galerius Maximian as Caesar. In his introductory notes to RIC VI, Londinium, Sutherland states that "Bastien is to be followed in regarding the umarked coins of Class I as an issue prepared in advance for Constantius' invasion of Britain in 296". Coin obverses depict right facing busts with bare neck truncation and laureate heads with the long laurel wreath ribbon laying on the neck. The Genius of the Roman People reverse depiction and inscription is standard with no mint mark. The inscriptional lettering is relatively large with delicate letterforms. Weight range is 10.5 to 8.75 gm Examplars of unknown Continental Mint invasion coinage RIC Volume VI, Lugdunum, Group I, (iv), folles, Class I, No. 14-21, c. 296, 10.5-8.75 gm. No. 14a - Diocletian: IMP C DIOCLETIANVS PF AVG R. GENIO POPV -- LI ROMANI No. 14b - Maximianus: IMP C MAXIMIANVS PF AVG R: GENIO POP -- VLI ROMANI No. 17a - Constantius: FL VAL CONSTANTIVS NOB C R: GENIO POPV -- LI ROMANI No. 17b - Galerius: C VAL MAXIMIANVS NOB C R: GENIO POPV -- LI ROMANI
