[10] However, the eastern Galician cities and towns were mostly populated by Poles and Jews,[11] with Polish people forming the largest group of urban inhabitants.

Galicia's leading social class were Polish nobles or descendants of Rus' gentry who had been Polonized in the past, but in the east of the province, Ruthenians (Ukrainians) were the majority of the peasants.

[23] Since the West Ukrainian People's Republic was not internationally recognized and Poland's boundaries had not yet been defined, the issue of ownership of the disputed territory was reduced to a question of military control.

[24] In Przemyśl, local Ukrainian soldiers quickly dispersed to their homes and Poles seized the bridges over the River San and the railroad to Lviv, enabling the Polish forces in that city to obtain significant reinforcements.

According to Richard Pipes, the first major pogrom in this region took place in January 1919 in the town of Ovruch, where Jews were robbed and killed by regiments of Kozyr-Zyrka affiliated with Symon Petlura's government.

[47] Nicolas Werth claims that armed units of the Ukrainian People's Republic were also responsible for rapes, looting, and massacres in Zhytomir, in which 500–700 Jews lost their lives.

Thanks to fast and effective mobilization in December 1918, the Ukrainians possessed a large numerical advantage until February 1919 and pushed the Poles into defensive positions.

[45] On December 9, 1918, Ukrainian forces broke through the outer defences of Przemyśl in the hope of capturing the city and thus cutting off Polish-controlled Lviv from central Poland.

[51] The Barthélemy mission proposed a demarcation line (February 28) leaving almost 70% of the East Galician territory to Ukrainians, and Lviv with oil fields to Poland.

[52][53] The Allied demands, which included the loss of significant amount of Ukrainian-held and inhabited territory, were however deemed to excessively favor the Poles by the Ukrainians, who resumed their offensive on March 4.

[51] On January 6–11 of 1919 a small part of the Ukrainian Galician Army invaded Transcarpathia to spread pro-Ukrainian sentiments among residents (the region was occupied by Hungarians and Czechoslovaks).

[citation needed] Further conflict with the Czechoslovak authorities would have led to the complete economical and political isolation of the Western Ukrainian People's Republic.

[57] At the same time, on May 23, Romania opened a second front against Ukrainian forces, demanding their withdrawal from the southern sections of eastern Galicia, including the temporary capital of Stanislaviv.

On June 8, 1919, the Ukrainian forces under the new command of Oleksander Hrekov, a former general in the Russian army, started a counter-offensive, and after three weeks advanced to Hnyla Lypa and the upper Stryi river, defeating five Polish divisions.

[61] The West Ukrainian government controlled the Drohobych oil fields with which it planned to purchase arms for the struggle, but for political and diplomatic reasons weapons and ammunition could only be sent to Ukraine through Czechoslovakia.

[58] In attempt to end the war, in January 1919 an Allied commission led by a French general was sent to negotiate a peace treaty between the two sides, prompting a ceasefire.

In February it recommended that the West Ukrainian People's Republic surrender a third of its territory, including the city of Lviv and the Drohobych oil fields.

[58][63] The Ukrainian side agreed to this proposal[58] but it was rejected by the Poles on the grounds that it didn't take into consideration the overall military situation of Poland and the circumstances on the eastern front.

The Poles argued that they need military control over the whole of Eastern Galicia to secure the Russian front in its southern part and strengthen it by a junction with Romania.

[63] The Poles launched an attack soon afterward using a large force equipped by France (Haller's Army), which captured most of the territory of the West Ukrainian People's Republic.

[68][69] On November 21, 1919, the Highest Council of the Paris Peace Conference granted Eastern Galicia to Poland for a period of 25 years, after which a plebiscite was to be held there, and obliged the Polish government to give territorial autonomy to the region.

[70][68] On April 21, 1920, Józef Piłsudski and Symon Petliura signed an alliance, in which Poland promised the Ukrainian People's Republic the military help in the Kyiv offensive against the Red Army in exchange for the acceptance of Polish–Ukrainian border on the river Zbruch.

In 1918, the Entente countries sought to form a common anti-Bolshevik front, which was to include the Polish, White Russian, Romanian and Ukrainian armies.

The sub-commission consisted of General Joseph Barthelemy (France) as chairman, Colonel Adrian Carton de Wiart (UK), Dr Robert Howard Lord (United States) and Major Giovanni Stabile (Italy).

Historian Christoph Mick states there was no systematic violence nor massacres of ethnic Poles by Ukrainians during the course of this war[80] but that both sides blamed each other for bloodshed.

[91] When Poles captured Lviv, a mixed group of Polish criminals released from prisons, militiamen and some regular soldiers pillaged the Jewish and Ukrainian parts of the city, and abusing local civilians.

[99] The head of the commission, Zamorski recommended imprisonment of culprits of the atrocities, while establishing friendly relationship with Ukrainian population based on existing laws.

Interned Polish civilians, soldiers and Catholic priests were held during the winter months in unheated barracks or railway cars with little food, many subsequently died from exposure to the cold, starvation and typhoid.

[111] According to a noted interwar Polish publicist, the Polish–Ukrainian War was the principal cause for the failure to establish a Ukrainian state in Kyiv in late 1918 and early 1919.

During that critical time the Galician forces, large, well-disciplined and immune to Communist subversion, could have tilted the balance of power in favor of a Ukrainian state.