Hilaire Belloc and G. K. Chesterton
The French-English polemicist Hilaire Belloc and the English author G. K. Chesterton were lifelong friends, collaborators, and intellectual allies. The two were considered inseparable and complementary forces until Chesterton's death in 1936.
Source: Wikipedia — Hilaire Belloc and G. K. Chesterton (CC BY-SA 4.0)