In 1996 Lego introduced the Imperial Armada replacing the Imperial Guard, it was the smallest set from the Imperial’s but was later re-released in 2001. They are based on the Spanish conquistadors and/or the Spanish Navy of the 16th and 17th century.
Unfortunately the Imperial Armada had no home base like the Imperial Soldiers with their El Dorado Fortress or the Imperial Guards with their trading post. The Imperial Armada did have 2 ships in the 6280 Armada Flagship and the 2001 remake 6291 Armada Flagship or Spaniard Ship.
They were the first Lego figures with conquistador or morion helmets. They had a white flag with blue boarder showing a crown above an anchor.
6244 Armada Sentry (Water Outpost)
Sentry was a 71 piece Pirates set with 1 minifig released in 1996. It includes an Imperial Armada guard shack with a jetty, a rowing boat and one soldier.
6280 Armada Flagship (Armada Galleon / Santa Cruz)
Released in 1996, the Armada Flagship was a 284 piece Pirates set with 3 minifigs. It includes all three members of Imperial Armada: Captain Valiant, the Admiral, and a soldier.
6291 Spaniard Ship (Armada Galleon)
This was a re-release of the earlier 6280 set for the 2001 remake of Pirates theme by Lego.