Law takes up a gap in the study of Christian missions in West Africa: the seventeenth-century Catholic efforts in Allada and Whydah, kingdoms on the Bight of Benin that Dahomey absorbed in the 1720s. Despite abundant printed documentation, no detailed study had been attempted, and general surveys handle the episode briefly and not always accurately.

Two things are done here. The first is narrative -- a fuller reconstruction of missionary enterprise from early Portuguese contact through the Dahomian conquests. The second is explanatory, asking why Africans responded to evangelisation as they did.

Kings, Law finds, were consistently more open to baptism than their chiefs, and he reads this politically. Royal authority was checked in practice by provincial governors and by the priesthoods of the local vodun; raising up a supreme god mirrored, and could serve, an expansion of the king's power. Whydah's rulers were meanwhile quarrelling openly with the python cult over offerings and attendance.