Aemilian Emperor of the Roman Empire from August AD 253 to October AD 253.
Aemilianus, also known as Aemilian, was Roman Emperor for three months in 253.

Commander of the Moesian troops, he obtained an important victory against the invading Goths and was, for this reason, acclaimed Emperor by his army. He then moved quickly to Italy, where he defeated Emperor Trebonianus Gallus, only to be killed by his own men when another general, Valerian, proclaimed himself Emperor and moved against Aemilian with a larger army.

With only three months in power, coins of Aemilian are definitely comparatively scarce - and expensive - compared to the rulers immediately before and after him.
An AE unit struck 253 AD in Viminacium
Obverse: IMP C EMIL EMILIANO AVG, drap. bust with laur. head right

Reverse: PMSC - OLVIM, Moesia standing between bull and Lion, AN XIV in exergue

Diameter: 26 mm
Die Orientation: 0 H
Weight: 8.8 g
No notes for this coin
Pick 180
An AR Antoninianus struck AD 253 in Rome
Obverse: IMP CAES AEMILIANVS P F AVG, radiate, draped and cuirassed bust right

Reverse: PACI AVG, Pax standing left, holding olive branch and transverse sceptre, with legs crossed, leaning on column

Diameter: 21 mm
Die Orientation: 12 H
Weight: 3.79 g
This is the only example of this rarer group II issue on CoinArchives.
RIC 19
An AE Sestertius struck 253 AD in Viminacium
Obverse: laureate, draped and cuirassed bust right; IMP C M AEMIL AEMILIANVS A

Reverse: Moesia facing, head left between bull walking right on left and lion walking left on right; PMS C_OL VII / AN XIV

Diameter: 24 mm
Die Orientation: -
Weight: 8 g
VII - IX 253 AD
AMNG 179; Pick-Martin 6