  From an astronomical and relativistic point of view, the Great War began with
the August, 1914 capture and imprisonment of the members of a German eclipse
expedition that had gone to the Crimea to look, at the request of Einstein, for
bending of starlight by the sun. And it ended in 1919 with the
Eddington-inspired measurements of that light bending from Principe and Sobral
and with the founding of the International Astronomical Union by scientists
from "the countries at war with the Central Powers." In between came
unprecedented, and in some ways unequaled, death and destruction. The
scientists lost were mostly too young to have made an impact (Henry Moseley and
Karl Schwarzschild are exceptions), but many of the best-known of the next
generation had, if citizens of the belligerent countries, served on the battle
lines, and most of the rest contributed in some other way. It may come as a
surprise to find that both theoretical physics and observational astronomy of
relevance to general relativity continued to take place and that there was a
certain amount of communication of results, information, and even goods in both
directions. The early post-war years saw something of a flowering of the
subject, before the majority of physicists turned their attention to quantum
mechanics and astronomers to stellar physics, though both had already been
under consideration during the war. War-based bitterness between French and
German scholars was surely part of the context in which Einstein and Henri
Bergson faced off on 6 April 1922, in a debate on the nature of time, as part
of an Einsteinian visit to Paris that had originally been planned for Fall,
1914.
