When Asimov's friend and then-agent Frederik Pohl became editor of Astonishing Stories and Super Science Stories later that year, Asimov submitted "Pilgrimage" to him. Pohl also rejected it, saying the ending was weak. Asimov continued trying to sell "Pilgrimage", rewriting it twice more and changing the title to "Galactic Crusade". Finally, on 15 August 1941, Asimov learned that Planet Stories editor Malcolm Reiss was interested in the story. Following yet another rewrite (removing the religious dimension that Campbell had suggested), Reiss accepted the story on 7 October 1941, running it in the Spring 1942 issue under the title "Black Friar of the Flame".
The story is set thousands of years in the future. The Lhasinu, a reptilian race native to Vega, rule a third of the galaxy, including Earth. The rest of the galaxy is occupied by a number of independent human planets which are content to maintain the status quo. Earth is, however, the center of a cult called Loarism, whose adherents make an annual pilgrimage there. The Loarists are content to allow the Lhasinu to rule Earth as long as their own cult is not interfered with. When the people of Earth rose up against the Lhasinu five hundred years earlier, the Loarists did not aid them, and the rebellion was crushed.
The story opens with Russell Tymball, a nationalist Earthman, gaining possession of a Lhasinuic dispatch ordering the evacuation of Earth's human population and the planet's destruction. This will deal a death-blow to Loarism, and set the stage for the Second Galactic Drive, a planned Lhasinuic offensive against the disunited human worlds of the galaxy. Tymball uses the dispatch to convince Loara Paul Kane, head of the Loarists, to join in a second Terran rebellion against the Lhasinu. When a young Loarist pilgrim named Filip Sanat discovers two Lhasinu skulking around the Memorial in New York, Earth's most sacred structure, discussing the upcoming destruction of Earth, he rushes out, rouses a crowd, and starts a riot. When the Lhasinu attempt to force their way into the Memorial to arrest Sanat, they are overcome by Tymball's rebels and a human mob. Within a day, the Lhasinu are driven from New York City, and Sanat is sent out of the Solar System to enlist the help of the other human worlds.
Six months later, the Lhasinu are closing in on Earth, while the fleets of several human worlds close in on the Lhasinu. The human alliance is close to breaking up when Sanat betrays Lunar Base to the Lhasinu, forcing the allied human fleets to fight in self-defense. The Lhasinu fleet attacking Earth is defeated. At the same time, a human fleet attacking the Lhasinuic Home Fleet in the Vega system is also victorious, and the Lhasinu are forced to surrender.
The multiple rewrites the story went through turned Asimov off rewrites. Most of Asimov's subsequent stories were published as he wrote them, or after a single revision.
After its initial publication in Planet Stories, "Black Friar of the Flame" was reprinted in a 1952 magazine published by Planet Stories called Tops in Science Fiction, much to Asimov's annoyance.