SMS Orjen[Note 1] was one of six Tátra-class destroyers built for the kaiserliche und königliche Kriegsmarine (Austro-Hungarian Navy) shortly before the First World War.

[2] The main armament of the Tátra-class destroyers consisted of two 50-caliber Škoda Works 10-centimeter (3.9 in) K10 guns, one each fore and aft of the superstructure in single, unprotected mounts.

[4] The Tátra-class ships did not play a significant role in the minor raids and skirmishing in the Adriatic in 1914 and early 1915 between the Entente Cordiale and the Central Powers.

[6] The Kingdom of Italy signed a secret treaty in London in late April 1915 breaking its alliance with the German Empire and Austro-Hungary and promising to declare war on the Central Powers within a month.

Austro-Hungarian intelligence discovered this and Admiral Anton Haus, commander of the Austro-Hungarian Navy, planned a massive surprise attack on Italian ports and facilities on the northern Adriatic coast, outside of interception range of the modern ships of the Regia Marina (Royal Italian Navy) stationed at Taranto.

The destroyer SMS Lika, which had been bombarding Vieste, was ordered to block her escape to the north while Helgoland stayed to the east to cut off her access to the Adriatic.

Lika scored the critical hit of the battle when one of her 66-millimeter shells broke Turbine's steam pipe and caused her to rapidly lose speed.

Haus ordered Seitz to take Helgoland, Saida and all six Tátra-class destroyers on a reconnaissance mission off the Albanian coast on the night of 22/23 November.

They encountered and sank a small cargo ship and a motor schooner carrying flour for Serbia; four Italian destroyers were unable to intercept them before they reached friendly territory.

On the night of 11/12 March 1917, Orjen, Balaton, Csepel and Tátra swept through the Strait of Otranto, but failed to sink the French cargo ship SS Gorgone that they encountered.

The scout cruisers and Orjen, among other ships, took advantage of the confusion to rejoin loyalist forces in the inner harbor where they were protected by coastal artillery.

Vice Admiral Miklós Horthy was informed on the morning of 28 October that an armistice was imminent, and used this news to maintain order and prevent a mutiny among the fleet.

Thus Emperor Karl I's government in Vienna asked the newly formed State of Slovenes, Croats and Serbs for help maintaining the fleet stationed at Pola and keeping order among the navy.

Emperor Karl I, still attempting to save the Empire from collapse, agreed to the transfer, provided that the other "nations" which made up Austria-Hungary would be able to claim their fair share of the value of the fleet at a later time.

All sailors not of Slovene, Croatian, Bosnian, or Serbian background were placed on leave for the time being, while the officers were given the choice of joining the new navy or retiring.

Furthermore, the newly formed state had also not yet publicly repudiated Emperor Karl I, keeping the possibility of reforming the Empire into a triple monarchy alive.

[16] On 3 November the Austro-Hungarian government signed the Armistice of Villa Giusti with Italy, ending the fighting along the Italian Front,[17] although it refused to recognize the transfer of Austria-Hungary's warships.

[18] Faced with the prospect of being given an ultimatum to surrender the former Austro-Hungarian warships, the National Council agreed to hand over the ships beginning on 10 November.

She was commissioned in the Regia Marina with the name Pola on 26 September, refitted and was assigned to the Venetian squadron from March 1922 where she made training cruises with machine engineering students to the Eastern Mediterranean.