HMS Theseus was an Edgar-class

Edgar class cruiser

The Edgar-class was a nine-ship class of protected cruiser built around 1891 for the Royal Navy.-Design:Crescent and Royal Arthur were built to a slightly modified design with a raised forecastle and a pair of 6 inch guns replacing the forward 9.2 inch gun, and are sometimes considered a...

 protected cruiser

Protected cruiser

The protected cruiser is a type of naval cruiser of the late 19th century, so known because its armoured deck offered protection for vital machine spaces from shrapnel caused by exploding shells above...

 of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. The Edgars were basically smaller versions of the Blake class

Blake class cruiser

The Blake class was a two-ship class of first-class protected cruiser built around 1890 for the Royal Navy.-Service:The two ships were obsolete by the outbreak of the First World War, and served as depot ships...

. Theseus was launched at Leamouth

Leamouth

Leamouth is the area to the west of the mouth of the River Lea at the River Thames at . The northern part of the area lies within a meander of the Lea; the southern part is bounded in the west by the former East India Docks, on two sides by the Lea and by the River Thames to the south...

, London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 in 1892 and commissioned on 14 January 1896.

Upon commission, she was part of the Special Flying Squadron. She was a tender ship to Cambridge from 1905 to 1913. In February 1913, Theseus joined the Queenstown Training Squadron.

When war broke out in 1914, Theseus joined the 10th Cruiser Squadron. On 14 October, Theseus, accompanied by her sister-ship HMS Hawke

HMS Hawke (1891)

HMS Hawke, launched in 1891, was the sixth British warship to be named Hawke. She was an Edgar-class protected cruiser.-Service:...

, were patrolling the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 when they were attacked by U-9

Unterseeboot 9 (1910)

SM U-9 was a German Type U 9 U-boat. She was one of 329 submarines serving in the Imperial German Navy , and engaged in commerce war during World War I. Her construction was ordered on 15 July 1908 and her keel was laid down by Kaiserliche Werft in Danzig...

. The submarines first torpedo missed Theseus but hit Hawke, igniting a magazine that caused a tremendously powerful explosion, that ripped much of the ship apart. Just 70 of her 594 crew survived.

Theseus was rearmed, along with bulges to her hull, which were added to enable her to take part in the Dardanelles Campaign. In 1916 she was deployed to the Mediterranean and was then sent to the White Sea

White Sea

The White Sea is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is surrounded by Karelia to the west, the Kola Peninsula to the north, and the Kanin Peninsula to the northeast. The whole of the White Sea is under Russian sovereignty and considered to be part of...

. In 1918 she was sent to the Aegean Sea

Aegean Sea

The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...

 to be charged with the mundane task of being a depot ship

Depot ship

A depot ship is a ship which acts as a mobile or fixed base for other ships and submarines or supports a naval base. Depot ships may be specifically designed for their purpose or be converted from another purpose...

. In 1919, Theseus had her final deployment, when she was sent to the Black Sea

Black Sea

The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...

. She returned to the UK

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

in 1920 and was scrapped the following year in Germany.