Pirates

Pirates was a LEGO theme introduced in 1989, running until 1997 and focused on the classic idea of Caribbean pirates that were pitted against soldiers of colonial empires. As the series progressed through the years, more factions were introduced and the older ones were phased out of production. The Pirates were one of the first two original factions in the theme to be introduced.

Imperial Guards
Imperial Guards was a Pirates subtheme introduced in 1989 that eventually replaced the Imperial Soldiers as main adversaries of the pirates. Some of the older Imperial Soldiers' sets that were still in production were re-categorized as part of the Imperial Guards faction until their discontinuation in 1995.

Imperial Armada
Imperial Armada was a subtheme of Pirates that was introduced in 1996 and only had 3 sets that lasted one year. The Armada replaced the Imperial Guards as adversaries of the pirates. Imperial Armada minifigures were based on the Spanish conquistadors and the Spanish Navy of the 16th and 17th century.

Islanders
The Islanders was a subthem of Pirates released in 1994, and briefly brought back in 2001. The Islanders were loosely based on natives of the Pacific islands based on their Enchanted Island, and introduced a third faction into the theme during the Imperial Guards subthem timeline. The Islanders were considered to be neutral, but were known to have pirate and Imperial prisoners. All Islanders sets were released during 1994, but only one set, Enchanted Island, was re-released in 2001.