Boston 1775 recounts a story of two Irish brothers who found each other on opposite sides during the Battle of Saratoga. After the battle the two armies were talking to one another across the river when the brothers spotted each other and rushed into the river towards one another. One had left Ireland for America and the other had joined the British Army.
I think I've read similar stories about battles between the English and French around that time. Still, it seems such an amazing coincidence that it's almost unbelievable.