'Mars II' was the Axis movement of Italian reinforcements for the Axis 'Blau' summer offensives of 1942 by Generalfeldmarschall Fedor von Bock’s Heeresgruppe 'Süd' of 1942 on the Eastern Front (spring 1942).

These reinforcements, supplementing the three divisions of Generale di Corpo d’Armata Giovanni Messe’s Corpo di Spedizione Italiano in Russia (Generale di Divisione Mario Marazzani’s 3a Divisione celere 'Principe Amedeo Duca d’Aosta', Generale di Divisione Vittorio Giovannelli’s 9a Divisione autotrasportabile 'Pasubio' and Generale di Divisione Luigi Manzi’s 52a Divisione autotrasportabile 'Torino'), took the form of the 8a Armata, which had been created on 25 January 1940 under the command of Generale d’Armata Adalberto Duca di Bergamo. After garrison service in northern Italy, the army had been disbanded on 31 October 1940.

Re-formed on 1 April 1942 under the command of Generale d’Armata Italo Gariboldi, the army was now earmarked for service on the Eastern Front. The 8a Armata, also known as the Armata Italiana in Russia, began to arrive on the Eastern Front in July 1942 to come under the control of Generaloberst Maximilian Freiherr von Weichs’s Heeresgruppe 'B'. The 8a Armata had 10 divisions, including the three inherited from the CSIR. The new divisions comprised Generale di Divisione Carlo Pellegrini’s 2a Divisione montagna 'Sforzesca', Generale di Divisione Edoardo Nebbia’s (later Generale di Divisione Francesco Dupont’s) 3a Divisione montagna 'Ravenna', Generale di Divisione Enrico Gazzale’s (later Generale di Divisione Vincenzo Robertiello’s) 5a Divisione 'Cosseria' and Generale di Divisione Enrico Broglia’s 156a Divisione da occupazione 'Vicenza'.

In addition to these four divisions, three new Alpini divisions (Generale di Divisione Luigi Reverberi’s 2a Divisione alpina 'Tridentina', Generale di Divisione Umberto Ricagno’s 3a Divisione alpina 'Julia', and Generale di Divisione Emilio Battisti’s 4a Divisione alpina 'Cuneense') were sent to the Eastern Front. These formations were added to Generale di Brigata Cesare Rossi’s 52a Divisione autotrasportabile 'Torino', Generale di Brigata Davide Borghini’s (later Generale di Brigata Gerolamo Pittagula’s) 9a Divisione autotrasportabile 'Pasubio', and Generale di Brigata Carlo Lombardi’s 3a Divisione celere 'Principe Amedeo Duca d’Aosta' already in the USSR as the Corpo di Spedizione Italiano in Russia.

The 8^th Army was organised as three corps: Generale di Corpo d’Armata Giovanni Messe’s (later Generale di Corpo d’Armata Francesco Zingales’s) XXXV Corpo d’Armata, Generale di Corpo d’Armata Giovanni Zanghieri’s II Corpo d’Armata and Generale di Corpo d’Armata Gabriele Nasci’s Corpo d’Armata Alpino.

The XXXV Corpo d’Armata included the three CSIR divisions; the II Corpo d’Armata included the 2^nd Divisione montagna, 3^rd Divisione montagnaand 5^th Divisione; and the Alpini Corps included the 2^nd Divisione alpina, 3^rd Divisione alpina and 4^th Divisione alpina. The 156^th Divisione da occupazione was under direct command of the 8^th Army and used largely behind the front on lines of communication, security and anti-partisan tasks.

In addition to these 10 divisions, the 8a Armata included two German divisions (Generalleutnant Arnold Szelinski’s 298^th Division and Generalmajor Rudolf Friedrich’s 62^nd Division), a Croat Fascist volunteer legion, and three legions of Italian 'Blackshirt' (Camicie Nere, or CCNN) Fascist volunteers.

After capturing Krasny Luch and Serafimovich, the 8^th Army halted on the Don river, where it held a wide front. Struck by the Soviet 'Uran' offensive in November 1942, the front held by the bulk of the 8a Armata was penetrated and shattered, and many of its formations were overrun while others undertook a gruelling retreat to successive defensive positions. In March and April 1943, the remnants of the 8a Armata returned to Italy for rest and reorganisation.

The Italian participation in operations against the USSR had proved to be extremely costly. The 8a Armata's losses from 20 August 1942 to 20 February 1943 totalled 87,795 dead and missing (3,168 officers and 84,627 other ranks) as well as 34,474 wounded and frostbitten (1,527 officers and 32,947 other ranks).