Several Greek and Roman writers recorded a lunar eclipse that occured before the battle between Alexander the Great's army and Persian forces at Gaugamela near Arbela (todays Erbil in northern Iraq). The date of the battle is given by Arrian as during the month Pyanopsion when Aristophanes was archon at Athens. This means early in the autumn (October) -330 or -329 in our calendar.

There was a large lunar eclipse on -330 September 20, but also a second one on -98 October 6. Both eclipses would date the battle to October as Arrian says, and both were visible in northern Iraq, but at different hours of the night. A strange coincidence is the fact that the two solutions for Pliny's quadruple (see separate report) and the two candidates for the Arbela eclipse are offset by exactly the same number of days: 232 (Julian) years + 16 days = 84754 days.

Moreover, it seems that a Babylonian clay tablet mentioning the battle at Gaugamela has been preserved by a rare coincidence. This tablet contains sufficient astronomical information to date the described battle to -330 October 1 as conventionally assumed.

Even though there are two solutions with 232 years offset for both Pliny's quadruple and the lunar eclipse before the battle at Gaugamela, the Babylonian clay tablet tilts the scales in favour of the conventional solution. However, if our dendrochronological results are correct, something must be wrong with the astronomical records in some way. Ultimately we have to decide which dating method we trust most, and why. Follow our argumentation here.