This article is based on an article originally written by Rick Priestley in the late 80's early 90's, I have adapted to update and add in the latest information whilst hopefully presenting it in a concise and easy to understand format. As such it may be superseded by official Games Workshop publications. Formative Armour A History of Space Marine Power Armour. Based on an article by Rick Priestley. Most humans who have any contact with Space Marines will know and recognise the most common types and patterns of Space Marine armour quite readily. However, there are other older types, patterns and marks which remain in service to this day and which are very different in their design. Some Space Marine Chapters use only a single type of armour while others make use of several different types. Many of the older variants have special associations for particular Chapters and may be worn by ceremonial guards or by elite units for example. Other Space Marine Chapters are less formal in their use of armour, mixing various types and marks into their fighting units with little or no regard for conformity. The degree of uniformity within a Space Marine Chapter varies a great deal from Chapter to Chapter and is often determined by historical precedent or tradition. The initial evolution of Space Marines and their armour occurred during the long period of Earth's isolation that preceded the rise of the Imperium and which later became known as the Age of Strife. The Age of Strife lasted from approximately the 26th millennium to the beginning of 31st (ie. roughly from 25000 AD to 30000 AD - further references to dates are given in terms of millennia). During these five thousand years the ancient pan-galactic human civilisation of the past broke down and was replaced by many thousands of local civilisations based around either a single solar system or, occasionally, a small cluster of nearby stars. The reason this happened is that warp travel (the means by which spacecraft travel throughout the galaxy) became dangerous and eventually impossible due to colossal disturbances in the fabric of the warp. These disturbances, known as warp storms, were caused by the growth of the Chaos Power Slaanesh. During the Age of Strife, Earth and the other planets of the Terran solar system were unable to communicate with other human worlds beyond the system, but maintained contact with each other. For much of this period the government of Earth held sway over the entire system, at other times Mars and the Moon were dominant. For much of the time the different worlds found themselves at war. During the 28th millennium Earth government broke down completely and the planet divided into dozens of inter-warring nations. After two and a half thousand years of continuous warfare little remained of the once sophisticated civilisation of the past. The planet had become a battleground fought over by techno-barbarian warlords and their warrior hordes. This was a dark time for the people of Earth: a time dominated by brutal rulers like Kalagann of Ursh, Cardinal Tang, and the most infamous of all, the half-mad half-genius Narthan Dume Tyrant of the Panpacific Empire. It was against this background of techno-barbaric warfare that the first Space Marines were created and the first Space Marine Armour type developed. Mk I, Thunder Armour Powered armour was originally developed before the Age of Strife and was included in the STC system. In fact it was so widespread that this is the sort of armour worn by virtually all the techno-barbarian warriors that dominated the Earth during the Age of Strife. So when the Emperor began his conquest of Earth his retinue was equipped and armed in the same way as those warriors of other Warlords. The power armour they wore was not the single enclosing power suits of later ages and advanced STC's but more basic forms. As such they offered no atmospheric protection or life-support facilities, these being unnecessary whilst fighting within the atmosphere of planets like Old Earth. The armour itself was of a fairly standard design with variances to the exact design due to the fact that their production was usually on a local basis, and they conformed to the personal tastes of the maker and commissioner. All types of this armour had certain pieces, underlying technology and design ethos in common. The helmet was conical based with a rounded top, round ear guards/filters and were open faced with some form of a clear visor, plus there was some form of adornment with typical examples being a topknot or a horse hair crest in the ancient Greco-Roman style. The main part of the armour was a massive powered torso, with a cuirass over it enclosing the chest and arms. Beneath this cuirass are the coiled energy cables that transmit power into the arms, effectively multiplying the wearers strength and fighting abilities by as much as three or four times. During the long period of the Unification Wars most fighting consisted of close combat, with warriors preferring to look the enemy in the eye, rather than use long range weapons, therefore the power of a warrior’s chest and arms was of paramount importance. This not to say Bolter weapons weren't employed. There was also the backpack, which provided the suit with power. Most of its bulk being occupied by cooling mechanisms meant to prevent the power unit from overheating. The warriors legs are not powered at all, but enclosed in tough padded breeches sometimes the warrior wears armoured greaves and armoured boots. These were not standard by any means, but were worn by many of the better equipped warriors and were common amongst the early Space Marines. The Emperors warriors bore his personal Thunderbolt and Lightning emblem on their breastplates in those days, predating the Imperial eagle which only became the symbol of the Imperium much later, and leading to the armour's common name of Thunder Armour and those that wore it the Thunder Warriors. By the latter stages of the wars to unify the Solar system the Emperors forces also had thigh armour, armoured boots and greaves, bearing a derivative of the Thunderbolt & Lightning emblem, as part of their armour. Warriors equipped this way fought during all the Emperor’s wars on Old Earth, as well as those on the Moon, Mars and other terraformed worlds of the Sol system which had Earth-type atmospheres at this time. This armour was originally equipped to the Emperors techno-barbarian forces, then to the Thunder Warrior regiments, the Custodian Guard and, when they were eventually created, the regiments of the Legiones Astartes. Space Marines were provided with this suit as their first armour. Mk I Armour was rarely seen worn by Space Marines near the end of the Great Crusade, though it does form the basis of the Custodian Guards Armour, and is unlikely to be seen at all on the 41st Millennium battlefield, though ceremonial units are sometimes equipped with them. It is safe to say that most if not all Imperial power armour is based, at least in part, from this type of armour.