The Battle of the Mediterranean was the name given to the naval campaign fought in the Mediterranean Sea during World War II.

Characteristics

For the most part, the campaign was fought between the forces of the Italian Royal Navy (Regia Marina), supported by other Axis naval forces, and the forces of the British Royal Navy, supported by other Allied naval forces.

Each side had three overall goals in this battle.  The first was to attack the supply lines of the other side.  The second was to keep open its own supply lines, the Axis to their own armies in North Africa and the Allies to supply the island of Malta.  The third was to destroy the ability of the opposing navy to wage war at sea.

Outside of the Pacific ocean, the Mediterranean saw the largest conventional naval warfare during the war. In particular, Allied forces struggled to supply and retain the key naval and air base of Malta.

Radar and fuel 

Italian warships had a general reputation as well-designed and good-looking.  But some Italian cruiser classes were rather deficient in armour.  All Italian warships lacked radar for most of the war, although this was partly offset by their good "rangefinder" and "fire-control" systems.  In addition, whereas Allied commanders at sea had discretion on how to act, Italian commanders were closely and precisely governed by Italian Naval Headquarters (Supermarina).  This could lead to action being avoided when the Italians had a clear advantage (e.g., During "Operation Hats"). Italian Naval Headquarters was conscious that the British could replace ships lost in the Mediterranean, whereas Italian Navy resources were limited and there was a terrible lack of fuel.

The Italian Navy entered the war with only one year of fuel required to operate normally. By 1943 the lack of fuel prevented naval operations far away from the coasts of Italy.

The Allies had "Ultra" intercepts from Bletchley Park, which predicted the Italian movements, and radar, which enabled them to locate the ships and to range their weapons at distance and at night. The better air reconnaissance skills of the Fleet Air Arm and their close collaboration with surface units were other major causes of the initial Italian defeats (like in the Battle of Cape Matapan).

Forces

The Axis forces in this campaign were:-
Italian Navy, Air Force and Army
German Navy (u-boat force), Air Force and Army

The Allied forces in this campaign were:-
British Navy, Air Force and Army
Australian Navy, Air Force and Army
New Zealand Navy, Air Force and Army
Greek Navy, Air Force and Army
French (at the beginning; later they were neutral)
United States (at the end)

History
On 10 June 1940, Italy declared war on Britain and France. On the following day, Italian bombers attacked Malta on what was to be the first of many raids.
 
The first clash between the rival fleets,  the Battle of Calabria, took place on 9 July 1940, just four weeks after the start of hostilities. This was inconclusive (neither side won), and was followed by a series of small ship actions (the battle of the Espero convoy,  battle of Cape Spada)  during the autumn.

In spring 1940 the British Royal navy attacked at Mers el Kebir (Algeria) the French navy of Vichy, sinking two battleships and other minor ships.
 
In November, the RN mounted an aerial attack  on the Italian fleet in Taranto harbour, crippling three capital ships and changing the balance of power in the Mediterranean.

Three months later the fleets clashed again at the Battle of Cape Matapan. This was a major Allied victory; three Italian cruisers were sunk, and a battleship damaged in a two-day battle ending in a night action.

Following this the Allies suffered heavy losses in the Battle of Crete, supporting the army when the island was invaded by the Germans.

In spring 1941 the Greek and Yugoslavian navy were destroyed and/or made captive by the Italians (with help from the German air force) during the Italo-German war in the western Balkans against Greece and Yugoslavia.

Following the battle of Crete in  the summer of 1941, the Royal Navy got the better of things in the central Mediterranean in a series of successful convoy attacks, (such as the Duisburg convoy and the Battle of Cape Bon) until the events  around  the First Battle of Sirte and the Raid on Alexandria in December swung the balance of power in the Axis favour.

The Italian Navy's most successful attack was when divers planted mines on British battleships during the raid on Alexandria harbour (19 December 1941). HMS Queen Elizabeth and HMS Valiant were sunk (but ten months later raised and returned to active service). During those ten months the Italian Navy enjoyed a temporary control of the Mediterranean sea (called by Mussolini's propaganda the Mare Nostrum, meaning "our sea").

A series of hard fought convoy battles (Second Battle of Sirte in March,  Operations Harpoon and Vigorous in June, and Operation Pedestal in August) were victories for the Axis but ensured Malta's survival, until the  Allies regained the advantage in November 1942.

In Sept 1943 with the Italian collapse and the surrender of Italian fleet, naval actions in Mediterranean  became  restricted to actions against U-boats and by small craft in the Adriatic and Aegean seas.

Major surface actions of the campaign
28 June 1940, Battle of the Espero Convoy. Italian convoy attacked, destroyer Espero sunk.
9 July 1940, Battle of Calabria. Inconclusive fleet action.
19 July 1940, Battle of Cape Spada. Cruiser action, Bartolomeo Colleoni sunk.
12 October 1940, Battle of Cape Passero.
11 November 1940, Battle of Taranto. Aerial attack on Italian fleet in harbour, 3 battleships sunk.
27 November 1940, Battle of Cape Spartivento. Inconclusive fleet action.
6-11 January 1941, Operation Excess. British convoy to Malta.
26 March 1941,battle of Suda Bay. British cruiser sunk by torpedo boats.
27-29 March 1941, Battle of Cape Matapan. Fleet action, 3 Italian cruisers sunk.
16 April 1941, Battle of the Tarigo Convoy. Italian convoy attacked.
20 May-1 June 1941, Battle of Crete. Series of actions supporting army in Crete, 9 British warships sunk.
July 1941, Operation Substance. British convoy to Malta.
September 1941, Operation Halberd. British convoy to Malta.
8 November 1941, Battle of the Duisburg Convoy. Axis convoy destroyed.
13 December 1941, Battle of Cape Bon. Italian convoy attacked.
17 December 1941, First Battle of Sirte. British convoy attacked.
19 December 1941, Raid on Alexandria. Manned torpedoes attack British fleet, 2 battleships were sunk and a destroyer damaged.
22 March 1942, Second Battle of Sirte. British convoy attacked.
June 1942, Operation Harpoon. British convoy attacked.
June 1942, Operation Vigorous. British convoy attacked.
August 1942, Operation Pedestal. British convoy attacked.
November 1942, Operation Stone Age. British convoy to Malta.
2 December 1942, Battle of Skerki Bank. Italian convoy attacked.
11 December 1942, Raid on Algiers. Manned torpedoes attack Allied shipping.
16 April 1943, Battle of the Cigno Convoy. Italian convoy attacked.

Major Axis and Allied amphibious operations
The following are the major amphibious operations staged during the Battle of the Mediterranean:
 25 February 1941, Allied assault on Kastelorizo.
 20 May 1941, start of the Battle of Crete, the Axis invasion of Crete.
 19 September 1942, Allied assault on Tobruk.
 3 November 1942 Italian landing in Corsica, and occupation of the island.
 8 November 1942, start of Operation Torch, the Allied invasion of Vichy-controlled Morocco and Algeria.
 9 July 1943, start of Operation Husky, the Allied invasion of Sicily.
 3 September 1943, start of the Allied invasion of Italy.
 8 September 1943, start of the Dodecanese Campaign, the failed Allied attempt to invade the Dodecanese Islands.
 9 September 1943, start of the Allied Salerno landings in Italy.
 22 January 1944,  start of Operation Shingle, the Allied landings at Anzio in Italy.
 15 August 1944, start of Operation Dragoon, the Allied landings in southern France.

Related pages
Italian Mare Nostrum

References
 Stephen Roskill: The War at Sea 1939-1945 Vol I (1954).
 Stephen Roskill: The War at Sea 1939-1945 Vol II (1956).
 Eric Groves: Sea Battles in Close-Up Vol II (1993). 

Mediterranean
1940 in Europe
1941 in Europe
1942 in Europe
1943 in Europe
1944 in Europe
1945 in Europe