Could in theory be in either the Exploration or Modern Age since it lasted from 1150 to the 19th century (With it's most popular festival, Ojude Oba dating back to 1896.)
IJEBU KINGDOM - EXPLORATION AGE CIV
From the growing influence of Ifẹ and legacy of Oduduwa emerged three brothers who founded Ijebu which rose to become an economic powerhouse along the West African coast. From entirely avoiding involvement in the practice of slavery and being among the earliest kingdoms along the West African coast to encounter sailors from afar to consistently reinforcing their lands with impressive fortifications. Ijebu was able to successfully cement itself as a strong economic powerhouse in the region. Whilst it did later decline in prominence and later declined due to exhausting wars and the growing threat of colonialism, establishing a monopoly on local trade became a challenge, one that it would go on to face.
Starting Bias:
Coast
Attributes
Diplomatic
Economic
Unique Ability - Those Who Swim in The Deep Sea
- Trade Routes you receive give +5 Gold
for every improved resource copied. +1 Food
and +1 Culture
if the Civ you are receiving the trade route from is based on a different continent
- Water buildings are 10% cheaper to build
Unique Improvement - Sacred Groves
- +2 Gold

, +3 if this Settlement is part of a Trade Network
- +2 Culture

to adjacent Buildings on coastal tiles
Unique Military Unit
Jagun Ṣakabula: Replaces the Arquebusier, 10% cheaper to produce, +5 Combat Strength when fortified, +3 Ranged Strength to technologically inferior units
Unique Civilian Unit
Oniṣowo: Replaces the Merchant. Gain a +5 Gold

bonus when creating a Trade Route
Civic Tree:
Agemo
Tier 1: Additional Happiness

from Resources with a Happiness

yield, unlocks Sacred Groves
Tradition - Agemo Festival: Settlements produce additional Food

and Influence

during Celebrations
Tier 2: Rural Districts in cities gain +1 Influence
Osugbo
Tier 1: +1 Settlement Limit
Tier 2: +2 Fortification Strength to units adjacent to Navigable Rivers, unlocks Eredo Sungbo
Tradition - Iwarefa: Towns provide extra Food

to Cities
Oru Toll
Tier 1: Water buildings also give +1 Science

if within a settlement in a Trade Network. Unlocks the
Jagun Ṣakabula
Tradition - Ọbu Ejirin: Bonuses from copied foreign resources are doubled
Tier 2: 25% more Influence

towards Diplomatic Actions.
Associated Wonder - Eredo Sungbo
- Must be built adjacent to an Urban District
- +3 Combat Strength to all Military Units within 2 tiles of the Wonder
- +3 Gold
Cities List:
• Ijebu-Ode

- Capital of Ijebu, today in Ogun State, Nigeria
• Ijebu-Igbo - Largest Ijebu town and 2nd largest town in Ogun State, Nigeria
• Ijebu-Ososa
• Ijebu-Ife
• Ago-Iwoye
• Ijebu-Remo
• Imagbon - Main location of the Battle of Imagbon
• Isonyin
• Ikorodu
• Ijebu-Iṣiwo
• Okorogbin
• Okemoyin
• Lekki
• Sagamu
• Ikenne
• Epe