From what I've been able to find out this was built around 1890 when
an anti-slavery campaign was undertaken by Congolese White Fathers. Slaves
were being rounded up to carry ivory to the coast and then being sold.
The missionaries landed buying slaves to save them, and adopting orphans.



Apparently the mortar used for these buildings was material taken from
ant hills, which might explain the disintegration.
My information is all informal and may not be correct.