Buhari - pictured here in 1977 with the then-King of Sweden Carl XVI Gustaf and Saudi Arabia's Sheikh Ahmed Zaki Yamani in 1977 - began his military career straight out of school. By the time this picture was taken, Buhari had risen to become a regional military commander.

But Nigeria refused to bend to Mr Buhari’s will. Almost 500 politicians and businessmen were arrested for corruption and sent to jail by military tribunals. A new currency was issued to flush out the stashes piled floor to ceiling in the homes of the elite. For many military men this purge was too close for comfort—and too uncompromising.