Located 40 kilometres (25 mi) south-east of Saigon, Phuoc Tuy Province lay on the coast between the mountains of southern central Vietnam and the alluvial plains of the Mekong Delta, dominating the approaches to Vung Tau and the main highway to the capital.   Approximately 60 kilometres (37 mi) east to west and 35 kilometres (22 mi) north to south, it was roughly rectangular. Mostly flat, it gradually sloped north, while the Nui Thi Vai, May Tao and Long Hai mountains rose in the south-west, north-east and south. The province was bounded to the north by Bien Hoa, Long Khanh, and Binh Tuy provinces, and to the south-east by the South China Sea .  Separate administratively, the Vung Tau peninsula projected south, with the city of Vung Tau at its tip containing a shallow water port of strategic importance due to its capacity to relieve congestion on the Saigon River . Phuoc Tuy was bisected by Route 2 running north to the provincial capital of Ba Ria, while Route 15 ran north-west linking Vung Tau to Saigon and was the main supply route for the movement of stores landed at the port, and Route 23 ran east from Ba Ria.  With just a quarter of the province used for agriculture, it supported a modest population of 104,636, most of which was concentrated in the south-west in approximately 30 villages and 100 hamlets, with major settlements at Ba Ria, Long Dien, Dat Do, Binh Gia and Xuyen Moc.   The majority were Vietnamese, while there were small numbers of Chinese, Montagnards , Cambodians and French.  Two-thirds were Buddhist , while the remainder were Catholic .  Most lived in poverty as farmers, fishermen, labourers, merchants or mechanics. Rice growing was the main industry, while fruit and vegetables were also cultivated, and coastal fishing was extensive. Charcoal kilns, sawmills, salt evaporation ponds and rubber plantations also provided employment.  
Of the 1,000 or more Space Marine Chapters thought to be in existence at the present time, a blessed few can trace their beginnings back to an age more than ten thousand standard years ago in the late 30th Millennium, when the blessed Emperor of Mankind still walked amongst mortals. In those days, the Emperor first created the Primarchs , 20 immortal superhumans blessed with extraordinary intelligence, charisma and sheer physical might who were to be his generals and closest comrades during the Great Crusade to reunite the scattered and long-isolated human colony worlds after the end of the Age of Strife . The Primarchs wielded powers the like of which are not known in the Imperium today, yet they were lost to the Warp in an accident deep within the Emperor's gene-laboratories beneath the fortress that would become the Imperial Palace and were scattered, still in their gestation capsules, to worlds across the galaxy by the will of the Dark Gods of Chaos . The first Space Marines of the nascent Imperium were also the creation of that era, each made using the genetic inheritance of one of the Primarchs, albeit diluted a hundred times, for no merely human body could contain such power. As each of the Primarchs were encountered in turn by Imperial Expeditionary Fleets during the progress of the Great Crusade, they became the natural and obvious leader of the Space Marine Legion created from their genetic material and with whom they had so much in common. In many cases the Primarch's adopted world became the new base of operations for their Legion and was known henceforth as that Legion's homeworld. The Primarchs then recruited their loyal followers from each of these world's peoples into the ranks of their Legion while others were given rights to draw fresh blood from suitable warlike worlds that were liberated as the Great Crusade progressed.