Frente Oriental was a military and political coalition formed during the Spanish Civil War, primarily composed of leftist parties. It aimed to unite various factions, including the Spanish Socialist Workers' Party and the Communist Party of Spain, to defend the Second Spanish Republic against the Nationalist forces led by Francisco Franco. The coalition was established in 1936 and played a significant role in the early stages of the war. However, internal divisions and external pressures weakened its effectiveness, ultimately contributing to the defeat of the Republican side in 1939. The Frente Oriental's legacy remains a symbol of leftist unity during a tumultuous period in Spanish history.