In the young Kingdom of Greece, it was considered as an opportunity for realizing the irredentist aspirations of the Megali Idea, and the Greek government sponsored uprisings against Ottoman rule in Thessaly, Epirus, and Macedonia in early 1854.

This led the Russian commander, Prince Mikhail Dmitrievich Gorchakov, to authorize the creation of a volunteer corps under Lieutenant General Salas in December 1853.

[4] Moreover, it appears that there were two independent companies, under the priest Konstantinos Doukas (or "Papadoukas") and Aristeidis Chrysovergis [el], who was one of the chief recruiters of the corps,[6] and later wrote a two-volume "History of the Greek Legion" (Ἱστορία τῆς ἑλληνικῆς λεγεῶνος, Odessa 1887–88).

[7] Russian personnel attached to the Greek corps was limited to one field officer, two instructor-captains, 16 sergeants, and a small drum and bugle detachment.

[10] The Balkan volunteers were barely formed when the Russian army, under the threat of an Austrian attack, was forced to evacuate the Danubian Principalities in July 1854.

[16] At this point, the thoughts of both the Russian command and the Greek volunteers increasingly turned to the Crimea, where British, French, and Ottoman forces had landed.

[16] General Alexander von Lüders supported their wish, and suggested that after the end of the war, the Greeks might be settled in the Crimea.

It appears that this suggestion found a favourable reception with the Emperor, since the Greeks could replace the Crimean Tatars who had surrendered to the allied forces.

24 December] 1855, the five companies of Greek volunteers, numbering 823 men, left Izmail for Odessa, where they arrived twelve days later.

The Odessa Greek community collected funds for their upkeep, and the corps was reinforced with new recruits, in large part from those volunteers who had been discharged in 1854, but also with new arrivals.

[20] At this time, a member of the princely Phanariote Mourouzis family who had followed the Russian withdrawal from Moldavia to Bessarabia, was appointed as commander of the Greek Legion.

[22] Urusov made recommendations for instilling discipline by means of a formal organization of the Legion; Mourouzis and the Sevastopol garrison's chief of staff, Prince Viktor Ilarionovich Vasilchikov [ru] were tasked with drawing up a draft.

[24] The hardships and disease, as well as the realization that the hoped-for liberation of the Balkans from Ottoman rule was receding into the distant future, also demoralized many volunteers; about a hundred resigned.

[23] In early April, the Greeks were withdrawn from the city itself to the environs, where Prince Mourouzis tried to improve the corps' discipline and training, and give it a more regular character.

[23] In an engagement against the French in July, Chrysovergis distinguished himself enough to be decorated and placed in charge of a part of the Russian line at Maly Kurgan.

However, only 150 men under Papathanasopoulos—an officer held in high esteem by Chrysovergis, but completely unmentioned in the Russian sources—stayed on, while the rest refused to obey and were discharged.

According to the historian Maria Todorova, "the files of the Russian war ministry are full of pleas by Greeks and Bulgarians from the beginning of 1856 who, left penniless, begged for a job or assistance".