  Asteroid pairs, two objects that are not gravitationally bound to one
another, but share a common origin, have been discovered in the Main belt and
Hungaria populations. Such pairs are of major interest, as the study of their
evolution under a variety of dynamical influences can indicate the time since
the pair was created. To date, no asteroid pairs have been found in the Jovian
Trojans, despite the presence of several binaries and collisional families in
the population. The search for pairs in the Jovian Trojan population is of
particular interest, given the importance of the Trojans as tracers of
planetary migration during the Solar system's youth. Here we report a discovery
of the first pair, (258656) 2002~ES$_{76}$ and 2013~CC$_{41}$, in the Jovian
Trojans. The two objects are approximately the same size and are located very
close to the L4 Lagrange point. Using numerical integrations, we find that the
pair is at least $360$~Myr old, though its age could be as high as several
Gyrs. The existence of the (258656) 2002~ES$_{76}$--2013~CC$_{41}$ pair implies
there could be many such pairs scattered through the Trojan population. Our
preferred formation mechanism for the newly discovered pair is through the
dissociation of an ancient binary system, triggered by a sub-catastrophic
impact, but we can not rule out rotation fission of a single object driven by
YORP torques. A by-product of our work is an up-to-date catalog of Jovian
Trojan proper elements, which we have made available for further studies.
