Complex sentence: By 1756 it was renamed the Bengal European Regiment -'European' indicating it was composed of white soldiers, not Indian sepoys-and when this was split in 1765 it became the 1st Bengal European Regiment.
Split into simpler sentences: By 1756 it was renamed the Bengal European Regiment -'European' indicating it was composed of white soldiers, not Indian sepoys. When this regiment was split in 1765, it became the 1st Bengal European Regiment.