[6] In the 15th and 16th centuries, the kingdom reached the height of its prosperity, expanding its territory, trading with European powers, and creating a remarkable artistic legacy in cast bronze, iron, brass, carved ivory, and other materials.

In the 15th century, Oba Ewuare is credited with turning Benin City into a city-state from a military fortress built by the Ogisos, protected by moats and walls.

[18] At its height in the 16th century, Benin dominated trade along the entire coastline from the Western Niger Delta, through Lagos reaching almost Accra in the West.

[20] Ruling in the late 16th century, Oba Ehengbuda was the last of the warrior kings; after his reign the empire gradually shrank in size, losing control over territories in the west.

[citation needed] In the late 19th century, the Kingdom of Benin managed to retain its independence and the Oba exercised a monopoly over trade which British merchants in the region found irksome.

[30] Gallwey was able to get Omo n’Oba (Ovonramwen) and his chiefs to sign a treaty which gave Britain legal justification for exerting greater influence over the Empire.

[33] The treaty itself does not explicitly mention anything about Benin's "bloody customs" that Burton had written about, and instead only includes a vague clause about ensuring "the general progress of civilization".

[33] A British delegation departed from the Oil Rivers Protectorate in 1897 with the stated aim of negotiating with the Oba of Benin regarding the trade agreement, which they felt he was not keeping.

In March 2021, institutions in Berlin, Germany and Aberdeen, Scotland announced decisions to return Benin Bronzes in their possession to their place of origin.

A general emancipation of slaves followed in the wake of British occupation[39] but Britain also imposed a system of forced labour in Benin[40] and in surrounding areas,[41] as they did throughout other parts of southern Nigeria.

[53] Humans were sacrificed in an annual ritual in honour of the god of iron, where warriors from Benin City would perform an acrobatic dance while suspended from the trees.

[56] After the son was installed as king, his mother – after having been invested with the title of Iyoba – was transferred to a palace just outside Benin City, in a place called Uselu.

Among the residences of the nobility, a compluvium channeled the rainwater into the impluvium in order to permit light and air through the walls since windows were absent among these structures.

The Village Regiments provided the bulk of the fighting force and were mobilized as needed, sending contingents of warriors upon the command of the king and his generals.

Logistics were organized to support missions from the usual porter forces, water transport via canoe, and requisitioning from localities the army passed through.

Movement of troops via canoes was critically important in the lagoons, creeks and rivers of the Niger Delta, a key area of Benin's domination.

While the head-on clash was well known, documentation from the 18th century shows greater emphasis on avoiding continuous battle lines, and more effort to encircle an enemy (ifianyako).

In 1603–04 for example, European cannon helped batter and destroy the gates of a town near present-day Lagos, allowing 10,000 warriors of Benin to enter and conquer it.

A strong mercantile relationship developed, with the Edo trading slaves and tropical products such as ivory, pepper and palm oil for European goods such as manillas and guns.

Visitors in the 16th and 19th centuries brought back to Europe tales of "Great Benin", a fabulous city of noble buildings, ruled over by a powerful king.

A fanciful engraving of the settlement was made by a Dutch illustrator (from descriptions alone) and was shown in Olfert Dapper's Naukeurige Beschrijvinge der Afrikaensche Gewesten, published in Amsterdam in 1668.

[78] The work states the following about the royal palace: The king's court is square and located on the right-hand side of the city, as one enters it through the gate of Gotton.

It is divided into many magnificent palaces, houses and apartments of the courtiers, and comprises beautiful and long squares with galleries, about as large as the Exchange at Amsterdam.

The buildings are of different sizes however, resting on wooden pillars, from top to bottom lined with copper casts, on which pictures of their war exploits and battles are engraved.

Most of the buildings within this court are covered with palm leaves, instead of with square planks, and every roof is adorned with a small spired tower, on which cast copper birds are standing, being very artfully sculpted and lifelike with their wings spread.

Nyendael's description was published in 1704 as an appendix to Willem Bosman's Nauwkeurige Beschryving van de Guinese Goud-, tand- en Slave-kust.

[81]British trader James Pinnock who visited the kingdom writes that he saw "a large number of men all handcuffed and chained" with "their ears cut off with a razor".

"[83] Scientific analysis of the brass (or "bronze") used to make the famous Benin plaques and other sculptures found that, beginning in the late 15th century, the metal (previously thought to have come from the Netherlands) began to derive from the Rhineland region of Germany.

Thus, he gave rise to the tradition of the subsequent Obas of Benin spending seven days and nights at Usama before proceeding to announce their royal names at Useh.

[citation needed] Aside from Benin City, the system of rule of the Oba in the empire, even through the golden age of the kingdom, was still loosely based upon the Ogiso dynasty's tradition, which was military protection in exchange for pledged allegiance and taxes paid to the royal administrative centre.