Royal Charles was an 80-gun first-rate three-decker ship of the line of the English Navy. She was built by Peter Pett and launched at Woolwich Dockyard in 1655, for the navy of the Commonwealth of England. She was originally called Naseby, named in honour of Sir Thomas Fairfax's decisive 1645 victory over the Royalist forces during the English Civil Wars. She was ordered in 1654 as one of a programme of four second rates, intended to carry 60 guns each. However, she was altered during construction to mount a complete battery of guns along the upper deck (compared with the partial battery on this deck of her intended sisters, on which there were no gunports in the waist along this deck), and so was reclassed as a first rate.