High Quality Content by WIKIPEDIA articles! The Type 23 frigate or Duke class is a class of frigate built for the United Kingdom`s Royal Navy. The ships are named after British Dukes, thus leading to the class being commonly known as the Duke class. The first Type 23 was commissioned in 1989, and the sixteenth, HMS St Albans was commissioned in June 2002. They form the core of the Royal Navy`s destroyer and frigate fleet.