Gaius Galerius Valerius Maximianus Augustus was Roman Emperor from 305 to 311.
He served with distinction as a soldier under Emperors Aurelian and Probus, and in 293 at the establishment of the Tetrarchy, was designated Caesar along with Constantius Chlorus, receiving in marriage Diocletian's daughter Galeria Valeria.
Galerius was promoted to Augustus in 305, and laboured for the rest of his rule to become the sole emperor. In vain, of course.
He died in late April or early May 311 from a horribly gruesome disease described by Eusebius and Lactantius, possibly some form of bowel cancer, gangrene or Fournier gangrene.
He served with distinction as a soldier under Emperors Aurelian and Probus, and in 293 at the establishment of the Tetrarchy, was designated Caesar along with Constantius Chlorus, receiving in marriage Diocletian's daughter Galeria Valeria.
Galerius was promoted to Augustus in 305, and laboured for the rest of his rule to become the sole emperor. In vain, of course.
He died in late April or early May 311 from a horribly gruesome disease described by Eusebius and Lactantius, possibly some form of bowel cancer, gangrene or Fournier gangrene.

(1)
Galerius
308-311 AD
Obverse:
GAL MAXIMIANVS PF AVG
Reverse:
GENIO AVGVSTI, Genius waring modius standing left holding patera from which liquid flows and cornucopiae
(2)
Galerius
AD 301
Obverse:
MAXIMIANVS NOB CAES, laureate head right
Reverse:
SACRA MONET AVGG ET CAESS NOSTR, Moneta standing left, holding scales and cornucopiae. Star in left field, B in right field.
(3)
Galerius
298-299 AD
Obverse:
Laureate head r.
Reverse:
Genius standing l., holding patera and cornucopia; TSA.
(4)
Galerius
308-309 AD
Obverse:
laureate head right; IMP GAL VAL MAXIMIANVS P F AVG
Reverse:
Genius standing left, pouring out patera and holding cornucopia; GENIO IMP_E_RATORIS / ·HTA·
(5)
Galerius
309-311 AD
Obverse:
laureate head right; IMP MAXIMIANVS P F AVG
Reverse:
Genius standing left, wearing chalmys, holding cornucopia, pouring libations from patera; GENIO A_VGVSTI/ crescent _A / SIS
(6)
Galerius
303 AD
Obverse:
Radiate, draped and cuirassed bust right from behind; GAL VAL MAXIMIANVS NOB C
Reverse:
Legend within wreath; VOT / X / F K
(7)
Galerius
299-300 AD
Obverse:
laureate head right; GAL VAL MAXIMIANVS NOB CAES
Reverse:
Genius standing left, wearing modius and chalmys, pouring libations from patera, holding cornucopia; GENIO POPV_LI ROMANI / Γ / ANT
(8)
Galerius
299 AD
Obverse:
radiate, cuirassed bust right; GAL VAL MAXIMIANVS NOB C
Reverse:
legend within wreath; VOT / . / X / T
(9)
Galerius
304-305 AD
Obverse:
laureate head right; GAL VAL MAXIMIANVS NOB CAES
Reverse:
Genius standing left, wearing modius and chalmys, pouring libations from patera, holding cornucopia; GENIO POPV_LI ROMANI • / Z / ANT
(10)
Galerius
300-301 AD
Obverse:
GAL VAL MAXMIMIANVS NOB CAES, Head of Galerius facing right, wearing laurel wreath
Reverse:
GENIO POPVLI ROMANI, Genius standing facing left, modius on head, nude except for chlamys on left shoulder (falls low); holding cornucopia in left hand and pouring libation from patera in right; K in left field; Epsilon over V in right field; ANT in exer
(11)
Galerius
307-308 AD
Obverse:
IMP C GAL VAL MAXIMIANVS P F AVG, Head of Galerius facing right, wearing laurel wreath
Reverse:
GENIO POPVLI ROMANI CMH (in ligature), Genius, wearing modius, nude, chlamys draped over left shoulder, standing facing left, pouring liquid from patera in right hand and holding cornucopia in left; SMNB in exergue