 Complete the following phrase:  In 1937, during the Spanish Civil War, Italians from the Corpo Truppe Volontarie began to serve in mixed Italo-Spanish Flechas Arrows units where the Italians provided the officers and technical personnel, while the Spanish served in the rank-and-file. One, the Flechas Azules Mixed Brigade Blue Arrows first served in Extremadura from April 1937 to the end of the 