Rome first became aware of and interested in the Niger area in 1851(1098) when merchants began finding markets in cheap slaves and exotic goods in the villages of the Beni(Benin). The Oludus(Yoruban) kingdom of Iliife (Ilé-Ifẹ) to the northeast was discovered in 1852(1099) and initial contact consisted of securing trade rights.
Circumvention and Exploitation
For the first few years the Roman traders were receiving very profitable deals, and soon the natives saw the demand for their goods and began raising the prices. Seeing the profits of the merchants, the Iliife kingdom established taxes on trade, and exerted greater dominion over the Beni tribes. This lead to the prices being necessarily increased, to the point that in 1857(1104) Roman traders began trying to sidestep the middleman natives in the delta by petitioning the Senate to allow a dedicated tradeship route with full access to the length of the River Niger. The legal ownership of the River was word of mouth, (most of) the Roman traders had been dissuaded from going ahead up the river themselves to trade by various reasons ranging from unfamiliarity with which trade posts had what, language difficulties, and non-serious threats by the African merchants. The petition was granted.
With the merchants working together or managing alone to purchase and maintain steamships, the natives were ruined. Some gave up and went to agriculture or other fields the Romans were not influencing, but others tried to stay in trade, unaware of the vastness of the Roman market forces. They realised that the Romans were quickly dominating the trade routes, eventually setting up their own posts even; exporting everything they found of value and further damaging the native economies.
By 1859(1106) there were five steamships making annual trips to the river and coasts, and in that year the ruined Beni and Oludus traders managed to destroy three of the ships. Several merchants were killed and those with access to the surviving ships clamoured to take advantage of the opening. As Roman citizens had been killed, the Senate demanded that Iliife (now in de facto political control of much of the region) find and extricate the perpetrators. Wary of Roman intentions, they took five destitute nobodies who may or may not have once been traders and executed them, sending the heads on the returning convoy. None of those executed were likely the perpetrators, but the Senate let the issue pass after the ageing crate of heads was opened and everyone needed to change their robes and take baths.
Minor situations would dot the next two years until late 1861(1108) when the merchantmen were attacked again. Only one of the ships were damaged beyond repair, but the Roman traders had become considerably annoyed and managed to get the Senate to send Imperial Vaporemes to bombard suspected villages. Merchants began arming their posts against native threats, and soon Imperial ships were patrolling the Niger as if it were the Luteus (Mississippi). This was also during the time of the Indian mutiny when Rome's policies on opposition was among its harshest.
With its growing confidence in the region, Rome had vaporemes further explore and map the Niger in 1863(1110)
By the 1880's(1124+) Rome's military presence in western Africa was constant. Any natives that had conflicts with Roman traders were eliminated with little restraint. Iliife was by this time very poor even though it 'enjoyed' Roman political support. Their city of Oko-edo(~Lagos) had more Roman than Oludus residents by this time.
In 1885(1132) the kingdom was attacked by Borgu raiders and failed to repulse them before they had done considerable damage to several cities including the capital (Iliife) and Oko-edo. Seeing the destruction and their failure to protect Roman nationals living in their kingdom, Rome took a patronising position and offered the young Oludus king Endoba protectorate status in exchange for 'autonomous' control over the Niger Delta and a mobile legion in Oko-edo. After much convincing he accepted.
Annexation and the Creation of the Province of Nigeria
King Endoba would find Roman influence increasingly infurating and meddling as the years wore on, he was said to have at one time hissed:
"I should have chosen death to me and my kingdom than this [agreement]".
In 1897(1144) Endoba would decree to his council (several of whom were either Roman born or Roman installed) that Rome was no longer welcome and that the kingdom would rise up against the tyrant. There was no way that Endoba was unaware that there were very pro-Roman supporters sitting in his government and council, so his speech has been considered by history to have been an intentional death wish. Officially he was 'deposed after a sudden flue and hospitalised' until his death on December 13th 1897, but in actuallity he was killed before he left the conference room on November 5th.
Oko-edo and the Niger delta (both with considerable Roman populations) were formally annexed into the colonies of Lacopalus and Nigeria on January 1st 1898(1145) while the remainder of the Iliife Kingdom was governed by a trusted member of Endoba's staff. This arrangement would last until 1913(1160) when the African kingdoms resistant to Roman influence began seriously threatening Iliife and Cæsar Felicissimus, more compassionate about the predicament of the Oludus, dissolved the kingdom's government, merged it with Nigeria and Lacopalus, and declared the creation of the Cæsarian province of Nigeria on Januray 15th with Georgos Tubul Aurefex as its first promagistrate. This action allowed Nigeria's development to start through Rome's systematic programmes. Cæsarian rule in Nigeria was much more benevolent than it had been under the Abadse or Senate-approved charter-rule, the native tribes were respected enough that they became less hostile, and eventually with the growth of infrastructure the populace within province became content and productive.
Although those within Nigeria's borders were dealt with much better than before, the tribes without were in no way correspondingly better treated. Territorial expansion was pursued up the Niger, by 1917(1164) Nigeria had doubled from its 1913 size and had produced a number of infamous characters. One being Tiberius Piscius Licinianus, the one-year proquaestor to promagistrate M. Lanatu Grattus, led a private mercenary army (a large number of which were Beni or Oludus) of 1500 against the Ashanti to the west(1923(1170)), decimating the kingdom and bringing thousands of slaves to the markets in Nigeria. Licinianus set himself up as ruler of the eastern Ashanti territories of Masaesylia.
The Fon, Tasad, and Guerrilla Wars
These incursions and the continued economic exploitation destabilised and further angered the native kingdoms, leading to the Fon (which had emerged replacing the Borgu through tribal warfare) allying to the Nupe Kingdoms and invading the northwest of Nigeria with 31 000 warriors in 1927(1174). The invasion was massacred by the Kushite Legion that met them, but the Fon War would not end until 1933(1180) with a tentative cease fire.
In 1929(1176) the Tasad kingdom to the northeast had formed pilium armed troops for its own 12 000 warrior invasion, but had met a defeat that ended up with their kingdom being divided up between the Owadai from the further east and Rome in 1931(1178).
This was also around this time that Samouri Torr's guerrilla strategies were spreading throughout Africa, a strategy which proved far more effective, resulting in the liberation of the Abadse controlled Bambotus and Licinianus' Masaesylia; and for the most part ending Roman expansion in western Africa by 1938(1185).
In the 2080's(1327+) increasing levels of pro-independence sentiment led to several small revolts but they were handled seriously for the trade income and political sphere of influence in western Africa and the Gulf of Aro(Guinea) was important to maintain.
With the beginning of the cold war between Rome and Sinica, Sinica played up independence again in Nigeria, but again the rioters were convinced to end the demonstrations following small token reforms.