|"Islands in the Sea"|
"Islands in the Sea" is a short story of alternate history, written by Harry Turtledove. It originally appeared in Alternatives, edited by Robert Adams, in 1989. It was reprinted in Departures and The Best Alternate History Stories of the Twentieth Century. The story is based in part on the Khazars, who are believed to have converted en masse to Judaism following a similar debate.
Half a century later, Muslim and Catholic emissaries visit a heathen Bulgar Khan named Telerikh, whose land lies between both religions, in an attempt to convert him to their respective religions. The Catholic delegation includes Niketas, a priest of Byzantine origins, one of the many Greek refugees now in communion with the Pope. After much proselytizing, Telerikh converts to Islam, in part because the Caliphate commands a stronger empire than the Pope (although Islam's tolerance of polygyny doesn't hurt). The participants realize that Christianity is doomed to remain in an isolated part of the world without a powerful empire to support it.
The Muslim success in converting Bulgaria without needing to send an army to conquer it creates an ominous precedent for the Christians: Muslim missionaries might follow through and penetrate deeper into Eastern, Central and Northern Europe, seeking to convert the many pagan peoples and fledgling kingdoms there. Should they succeed, Christian lands in Western Europe will remain isolated enclaves, Christian islands in a Muslim sea.
In "Islands in the Sea," one Catholic emissary makes the statement that Jesus stated that no more prophets would follow after John the Baptist. This statement is not recorded in any of the Gospel, nor is there any indication that it was part of Christian dogma during the 700s AD. When asked about this statement, Turtledove stated that it was not a Christian belief, yet in the story he attributes it as one.
In Islam, there is a major doctrine that Muhammad is "The Seal of the Prophets" and no more prophets would follow him, Anyone claiming to a "Successor Prophet" to Muhammad or acknowledging such a Successor is very much of a heretic in Muslim terms. In the divergent timeline of the story, where Islam was so much stronger than in OTL, Christianity might have emulated Islam and developed a similar doctrine against the Prophet Muhammad himself.
- In High Places, the third volume of the Crosstime Traffic series, which depicts a timeline in which the Black Plague wiped out 80% of the population of Europe, allowing Islam to establish states in the depopulated continent.