These were powered by sixteen coal-fired Marine-type water-tube boilers, although they were later altered to use fuel oil that was sprayed on the coal to increase its burn rate.

On 10 May, she was commissioned to begin sea trials, which were interrupted to escort Hohenzollern—Kaiser Wilhelm II's yacht—first to the Kiel Week sailing regatta and then for the Kaiser's annual summer cruise to Norwegian waters.

[7][8][b] The ship's stint in the main fleet's reconnaissance force was to be short-lived; already on 3 November, she was ordered to join the battlecruiser Goeben to form the Mittelmeerdivision (Mediterranean Division), under the command of Konteradmiral (Rear Admiral) Wilhelm Souchon.

[3][10] In April, the Great Powers decided to implement a blockade of Montenegro to force the government to end the Siege of Scutari and allow the city to fall under the control of Albania.

Breslau joined an international naval force in the Adriatic Sea that included warships from Britain, France, Austria-Hungary, Italy, and Russia.

After the Montenegrin government withdrew from the city, the international force sent landing parties ashore at the mouth of the Bojana and then move overland to Scutari.

During this period of rest, her crew and that of the German station ship Loreley helped to suppress a major fire in the French embassy in the city, and then assist with cleanup of the flood damage.

After getting underway again in late October, Breslau initially cruised in the eastern Mediterranean, and then in early January 1914, she returned to the mouth of the Bojana.

Souchon gave instructions to both vessels' crews in the event that the tensions created over the assassination of Archduke Franz Ferdinand led to war in Europe.

On 1 August, as the July Crisis spiraled out of control, Breslau returned to Durazzo to pick up the ten men who had been left at the embassy.

On 3 August 1914, Souchon's two ships were steaming off Algeria; shortly after 06:00, Breslau bombarded the embarkation port of Bône while Goeben attacked Philippeville.

[14] On 8 August, Goeben and Breslau met the collier off the island of Donoussa near Naxos, and two days later they entered the Dardanelles, under escort of an Ottoman torpedo boat.

By 22 October, the situation was resolved, and the Ottoman war minister, Enver Pasha, ordered the fleet to mobilize and prepare for offensive operations against Russia.

[15] On the evening of 27 October 1914, Midilli and the rest of the Ottoman fleet left the Bosporus and steamed into the Black Sea, ostensibly to conduct maneuvers.

They set the port's oil tanks on fire, damaged seven merchant ships, and sank Nikolai of 1,085 gross register tons (GRT).

[21] On 17 November, she sortied with Yavûz Sultân Selîm, under the command of Souchon, in an attempt to intercept the Black Sea Fleet as it returned from bombarding Trebizond.

Midilli discovered the Russian ships off Cape Sarych, the southern tip of the Crimea in poor visibility at short range.

[23] A month later, on 23 December, Midilli sortied to rendezvous with Yavûz Sultân Selîm off Sinope, and in the darkness the following morning she encountered the Russian transport Oleg, which was intended to be sunk as a blockship in Zonguldak.

[24] Midilli conducted a series of sorties against the Russians in early 1915, including an operation in concert with the cruiser Hamidiye in January, during which they inadvertently came into contact with the Black Sea Fleet.

Midilli and Yavûz Sultân Selîm provided the covering force for the attack, which failed after the cruiser Mecidiye struck a mine and sank off Odessa.

On 27 February, she was used to quickly transport 71 officers and men of a machine-gun company and a significant stock of supplies and munitions to Trebizond, which was then under heavy pressure from the Russian army.

On 11 March, Midilli made another run, this time carrying 211 soldiers and twelve barrels of fuel and lubricating oil, which were successfully landed on the 13th.

Midilli then turned north and sank a Russian sailing vessel off Tuapse before running into the powerful dreadnought battleship Imperatritsa Ekaterina Velikaya.

[32] In July, Midilli and Yavûz Sultân Selîm sortied to support the Ottoman counterattack at Trebizond, which broke the Russian lines and advanced some 20 km (12 mi).

She then rejoined Yavûz Sultân Selîm for the return to the Bosporus, during which the two ships evaded strong Russian forces attempting to intercept them.

Heavy use of smoke screens and a rain squall allowed Midilli to break contact with her Russian pursuers, and she reached the Bosporus early the following morning.

While Midilli was at sea, a Russian force including Imperatritsa Ekaterina Velikaya, which had by then been renamed Svobodnaya Rossiya, raided the Bosporus.

[37][f] On 20 January 1918, Midilli and Yavûz Sultân Selîm left the Dardanelles under the command of Vice Admiral Hubert von Rebeur-Paschwitz, who had replaced Souchon the previous September.

[39] Outside the straits, in the course of what became known as the Battle of Imbros, the two Ottoman ships surprised and sank the monitors Raglan and M28 which were at anchor and unsupported by the pre-dreadnoughts that should have been guarding them.

Rebeur-Paschwitz then decided to proceed to the port of Mudros; there the British pre-dreadnought battleship Agamemnon was raising steam to attack the Ottoman ships.