- Borno slave-raids on the hill communities (16th–19th c.) — annual *salla* raids by Kanem-Borno mounted columns into Sayawa, Zaar, Jarawa and Pa'a country; the captives feed the trans-Saharan slave market at Kuka.
- 1809–1840s — Bauchi jihad consolidation — Yakubu dan Dadi's wars against Yamaltu, Dass and the Bolewa; the hill peoples (Sayawa, Zaar, Jarawa, Warji) resist conversion and pay tribute under armed escort. The structural grievance — Muslim emirate ruling non-Muslim hill chiefdoms — is set here and recurs in every post-1991 crisis.
Bauchi State · Crisis deep dive
Pre-colonial (pre-1900)
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.