- Creation of Adamawa State (27 August 1991) — Gongola is split. The Bachama, Mumuye, Chamba and Mambila of the south go into Taraba; the Fulbe emirate of Yola and the highland communities of the Mandara go into Adamawa. The fault-line is fixed.
- Boko Haram precursor — Yan Izala / Izala doctrinal disputes (1990s) — the Izala reformist movement is strong across Yola and Mubi; the doctrinal break between Izala and Tarbiya groups foreshadows the post-2002 jihadi formations.Northern Abandonment Cycle
Adamawa State · Crisis deep dive
Abacha · Transition (1993–1999)
Methodology
Tier 1 · primary
Courts. Gazettes. National archives.
Tier 2 · corroborating
OCCRP. HRW. BudgIT. TheCable.
Tier 4 · tertiary, flagged
Wikipedia only where primary is pending. Always labelled.