Roman helmets
The Roman galea (helmet) evolved over time. Click on image for full-size view.

Montefortino helmet
The first example of this helmet was uncovered in a Celtic burial in Montefortino, Italy, with similar types found in Spain and Gaul. In use from 300 BC to the 1st century AD with continuing modifications. Montefortino helmets have a conical shape with a raised central knob, and a protruding neck guard as well as cheek plates to protect the sides of the head. Surviving examples often have missing cheek pieces, which may have been leather. Romans sometimes inscribed their names on their helmets. Early helmets are decorated with a "rope"-type pattern around the edge, and "pinecone"-type patterning on the crest knob. From the period of the Marian reforms of 100 BC, simple, cheap, undecorated but effective helmets were mass-produced for the mainly poor legionaries.
The first example of this helmet was uncovered in a Celtic burial in Montefortino, Italy, with similar types found in Spain and Gaul. In use from 300 BC to the 1st century AD with continuing modifications. Montefortino helmets have a conical shape with a raised central knob, and a protruding neck guard as well as cheek plates to protect the sides of the head. Surviving examples often have missing cheek pieces, which may have been leather. Romans sometimes inscribed their names on their helmets. Early helmets are decorated with a "rope"-type pattern around the edge, and "pinecone"-type patterning on the crest knob. From the period of the Marian reforms of 100 BC, simple, cheap, undecorated but effective helmets were mass-produced for the mainly poor legionaries.

Coolus helmet
The coolus was a simple hemispherical brass helmet (some were spun on a lathe rather than hammered to shape) with a turned or cast soldered- or riveted-on crest knob. It was fairly plain, except for some ridges or raised panels on the cheekpieces.
The coolus was a simple hemispherical brass helmet (some were spun on a lathe rather than hammered to shape) with a turned or cast soldered- or riveted-on crest knob. It was fairly plain, except for some ridges or raised panels on the cheekpieces.

Imperial Gallic helmet
Imperial Gallic helmets, first made by Celtic craftsmen in Gaul, have a pair of distinctive embossed eyebrows on the forehead region and tend to be carefully made and elaborately decorated. They have a sloped neck guard with ribbing at the nape, projecting ear guards, brass trim and decorative bosses.
Imperial Gallic G
The Gallic G was the typical legionary helmet used from the mid-first century until the early second century AD. The best example was found in the Rhine River at Mainz-Weisenau and is now exhibited in Worms, Germany. Helmets of this style can definitely be dated to the Boudican revolt of AD 61 based on fragments found in rubbish pits at Colchester (now reassembled and displayed at the Colchester Castle Museum). The carrying handle seen on the Weisenau original may date it slightly later, as none were present with the Colchester fragments. The brass rosettes on this resemble those found on the Corbridge type lorica segmentata. Therefore these two pieces of equipment are often portrayed together in modern reconstructions.
Imperial Gallic helmets, first made by Celtic craftsmen in Gaul, have a pair of distinctive embossed eyebrows on the forehead region and tend to be carefully made and elaborately decorated. They have a sloped neck guard with ribbing at the nape, projecting ear guards, brass trim and decorative bosses.
Imperial Gallic G
The Gallic G was the typical legionary helmet used from the mid-first century until the early second century AD. The best example was found in the Rhine River at Mainz-Weisenau and is now exhibited in Worms, Germany. Helmets of this style can definitely be dated to the Boudican revolt of AD 61 based on fragments found in rubbish pits at Colchester (now reassembled and displayed at the Colchester Castle Museum). The carrying handle seen on the Weisenau original may date it slightly later, as none were present with the Colchester fragments. The brass rosettes on this resemble those found on the Corbridge type lorica segmentata. Therefore these two pieces of equipment are often portrayed together in modern reconstructions.

Imperial Gallic H
The Gallic H has different style eyebrows and a more sloping neck guard. The most complete example of this type is from Lech, near Augsburg, Germany. Other datable helmets indicate a trend toward these more sloping neck guards in the last half of the first century, which continued through the second and third centuries. However, as both styles of neck guard were clearly used side by side, it was likely a matter of personal preference and/or armory issue of what type could be worn by a particular Roman soldier.
The Gallic H has different style eyebrows and a more sloping neck guard. The most complete example of this type is from Lech, near Augsburg, Germany. Other datable helmets indicate a trend toward these more sloping neck guards in the last half of the first century, which continued through the second and third centuries. However, as both styles of neck guard were clearly used side by side, it was likely a matter of personal preference and/or armory issue of what type could be worn by a particular Roman soldier.

Imperial Gallic I
The Gallic I differs from the H only by being made of the cupric alloy “orichalcum” (brass) instead of iron. The original was found in the Rhine River at Mainz, and bears the inscription of a soldier named L. Lucretius Celeris of Legio I Adiutrix. This Legion was stationed at Mainz from 71-86 AD. It had an Italian style “twist on” crest holder, rather than the Gallic style “slide-on” crest. All three brass helmets found had feather holders, which occur only rarely on iron ones, so they may suggest a higher rank, perhaps that of optio.
The Gallic I differs from the H only by being made of the cupric alloy “orichalcum” (brass) instead of iron. The original was found in the Rhine River at Mainz, and bears the inscription of a soldier named L. Lucretius Celeris of Legio I Adiutrix. This Legion was stationed at Mainz from 71-86 AD. It had an Italian style “twist on” crest holder, rather than the Gallic style “slide-on” crest. All three brass helmets found had feather holders, which occur only rarely on iron ones, so they may suggest a higher rank, perhaps that of optio.

Imperial Italic helmet
Imperial Italic helmets lack eyebrows and were roughly made, although improved over time. The wars of Trajan (AD 98-117) saw the wicked Dacian falx, a two-handed sickle-like sword, reach over Roman shield walls to puncture helmets. The Romans consequently added field-modifications of cross-bracing reinforcing bars to the helmet skull for extra protection. The crossbars became a standard feature of Roman helmets from 125 AD through the latter 3rd century.
Imperial Italic D
The Italic D is a highly-decorated mass-produced helmet. Although it may be a centurion's helmet, the surviving fore and aft crest attachment hooks suggest it belonged to a regular soldier. It was probably produced by a single workshop for soldiers willing to pay more for flasher headgear.
Imperial Italic helmets lack eyebrows and were roughly made, although improved over time. The wars of Trajan (AD 98-117) saw the wicked Dacian falx, a two-handed sickle-like sword, reach over Roman shield walls to puncture helmets. The Romans consequently added field-modifications of cross-bracing reinforcing bars to the helmet skull for extra protection. The crossbars became a standard feature of Roman helmets from 125 AD through the latter 3rd century.
Imperial Italic D
The Italic D is a highly-decorated mass-produced helmet. Although it may be a centurion's helmet, the surviving fore and aft crest attachment hooks suggest it belonged to a regular soldier. It was probably produced by a single workshop for soldiers willing to pay more for flasher headgear.

Imperial Italic G
The first Italic G helmet was found in a cave near Hebron, Israel, and thought to be captured war booty of the Jewish Zealots of the Bar Kochba Revolt during the reign of Hadrian (133-135 AD). There are brass lunate decorations applied between the crossbars.

Imperial Italic H
The Italic H Neidermormter helmet is made of iron or bronze, and is heavily decorated with a very deep neck guard. The cross bracing across the skull is embossed, rather than applied, with a dome-shaped knob at the crown. It is dated to the late Antonine or Severan eras, around 180-235 AD.
The Italic H Neidermormter helmet is made of iron or bronze, and is heavily decorated with a very deep neck guard. The cross bracing across the skull is embossed, rather than applied, with a dome-shaped knob at the crown. It is dated to the late Antonine or Severan eras, around 180-235 AD.

Trooper-helmet
The so-called Roman "Trooper-helmet" offered on eBay and internet sites everywhere is not allowed. It is inaccurate with soldered-on eyebrows, lobster-tail neck-guard, wrong shape cheek-guards, and a permanently mounted crest. Please do not purchase it! For the same price you can buy an accurate helmet that won’t cause the authenticity officer to smite you with his baton!
MORE INFO ON ROMAN HELMETS HERE
The so-called Roman "Trooper-helmet" offered on eBay and internet sites everywhere is not allowed. It is inaccurate with soldered-on eyebrows, lobster-tail neck-guard, wrong shape cheek-guards, and a permanently mounted crest. Please do not purchase it! For the same price you can buy an accurate helmet that won’t cause the authenticity officer to smite you with his baton!
MORE INFO ON ROMAN HELMETS HERE

Helmet Crests
Crests can be worn on parade, along with cloaks, but generally not in combat where they can interfere with our shields in vallum and testudo formations. Crests are not shown on Trajan’s Column, but they are seen on Antonine monuments and the Column of Marcus Aurelius. They can be tied with leather thong or wired.
Crests can be worn on parade, along with cloaks, but generally not in combat where they can interfere with our shields in vallum and testudo formations. Crests are not shown on Trajan’s Column, but they are seen on Antonine monuments and the Column of Marcus Aurelius. They can be tied with leather thong or wired.
Below: Roman cavalry helmets with face-plates. All three types are Imperium-Romana club helmets.