The Royal Fortune was a Man O' War captained by the pirate and Sage Bartholomew Roberts from 1719 to 1722. Before that, the ship was known as Nosso Senhor da Compreensão, and formed a part of the Portuguese Navy.
During their mission to acquire several blood vials in order to open the Observatory, the pirates Bartholomew Roberts and Edward Kenway captured the Nosso Senhor da Compreensão off the coast of Mexico in 1719. Soon thereafter, the pirates escape with the ship and sunk the pursuing Portuguese fleet. Afterwards, Roberts took the ship for himself and named it the Royal Fortune.
Roberts retained control of the Royal Fortune for three years, until Kenway pursued him to Príncipe in order to retrieve the Crystal Skull in Roberts' possession. Upon seeing Kenway approaching, Roberts jumped from a cliff onto the Fortune to try to escape.
While the Fortune was bigger and more heavily armed, it was slower than the Jackdaw, allowing Kenway to catch up with it. After reaching the open sea, the Royal Fortune came under attack from the Royal Navy and Spanish Navy, both of which were also after Roberts. The Jackdaw disabled the ship, allowing Kenway to board it, kill Roberts, and retrieve the skull. The Royal Navy then captured the Royal Fortune soon after.
Its sails and figurehead were later recovered by Kenway's Pirate fleet.
- Nosso Senhor da Compreensão is Portuguese for "Our Lord of Understanding"; a reference to the Father of Understanding.
- The Royal Fortune was one of the few vessels that could fire from the stern, hitting ships behind her. She also used fire barrels, a tactic typically associated with schooners.
- The Royal Fortune is one of the few ships that the player can pilot which isn’t the Jackdaw – the only others are the Jacobite, the Queen Anne's Revenge, and the Revenge.
- Before its capture by Roberts, it was the only Portuguese-named ship of the Portuguese Fleet as the other ships's names are Spanish.
- Historically the Fortune was attacked by two British Men O' War with one called the HMS Swallow where its full broadside managed to kill Roberts and forced the crew to surrender. In-game, it was attacked by four frigates of the Spanish and the Royal Navy, though the Spanish did not became that active in pirate hunting. The HMS Swallow did appear in the novelization as described by Edward, replacing the four frigates in the game, which also attacked the Jackdaw while pursuing the Fortune.
- If the player looked closely, the Fortune has a lesser number of cannons when Roberts captured it, considering that the upper gun decks do not have any cannons while when it was still serving the Portugese Navy, it had a full number of cannons in each gun deck.
- In the fleet, the Nosso Senior da Compreensão is observed to be level 70 when looking through the spyglass. When it becomes the Royal Fortune, the spyglass shows it to be level 36.
- The Fortune's model was seemingly re-used in Assassin's Creed: Rogue for the Gang Men O' War though it had several modifications.
- If Edward defeated all legendary ships like the El Impoluto or the HMS Prince before starting Black Bart's Gambit, the Fortune has a charged attack despite not possessing a naval ram and it could only deal half the damage that the Jackdaw could do to other ships.