25 BC (0): I cancel the Galley at Bjordvin. It could never leave our waters south. Did you notice the glaciers? Starting barracks instead. Increasing science rate to 100%.
10 BC (1): Great Lighthouse BIDL

Timbuktu now has 5 defenders, one north, one south (on the rice). I decide to pillage the rice to slow down Timbuktu but realize that we won't take it with the knowledge we have. Promoting an axe two cover and loosing it at 66%. Cleaing up with two other that are sent out to harrass. Rest is going southeast.
5 (2): St. Patrick is born in Uppsala. Send him to Nidaros to settle and generate money and hammers.
20 (3): Monotheism is in. Going for IW.
35 (4): As Timbuktus borders expand, Kumbi Saleh becomes completely worthless. Timbuktus defense is now at 60% and 7 Skirmishers defend it. That's too much for our axes. We'll come back later.
50 (5): Discover Gao, that is defended by three Skirmishers at 20%.
Btw. Did you know that cover is more useful against archers attacking and defending at 30% that city garrison (25%)? Just wanted you to know and to promote accordingly as long as we dealwith archers mainly as we've got some CR but no cover promotions yet
65 (6): Mansa offers peace for archery. No.
95 (8): Asoka captures Teoihuacan. We loose 3 axes at Gao and kill 2 skirmishers.
110 (9): Pyramids BIDL. Another skirmisher is killed in Gao and we raze it, capuring some 60 or 70 gold and 2 workers.
125 (10): The Parthenon is BIDL. Intersting: Timbuktu is now only defended by 2 skirmishers. Since I left the cities Mansa has drawn those troops elsewhere.
The rest of my turn I spent healing troops and finally converging 11 axemen to Timbuktu. Asperger should be able to take Timbuktu in the next 2 or 3 turns (arriving in 1). He has to care that 3 skirmishers from the east will not reach Timbuktu before it is captured. And it is to be expected that another 2 to 3 skirmishers are put into Timbuktu before we can attack. So do anything you can to hold off those 3 or we won't capture it.
Once we've captured Timbuktu, I would expect Mansa to capitulate, but he can't, since we didn't research Feudalism yet. And this is needed for vassalage. So I would suggest to simply make peace for a technology and force Mansa into Capitulation or eliminate him later.
Then it should be time for heavy trading as, you know, we're traders after all
Bring Mansa Musa down! 