Operation Barclay was an Allied

Allies

In everyday English usage, allies are people, groups, or nations that have joined together in an association for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out between them...

 deception

Deception

Deception, beguilement, deceit, bluff, mystification, bad faith, and subterfuge are acts to propagate beliefs that are not true, or not the whole truth . Deception can involve dissimulation, propaganda, and sleight of hand. It can employ distraction, camouflage or concealment...

 plan in support of the invasion of Sicily, in 1943, during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

.

This operation was intended to deceive the Axis

Axis Powers

The Axis powers , also known as the Axis alliance, Axis nations, Axis countries, or just the Axis, was an alignment of great powers during the mid-20th century that fought World War II against the Allies. It began in 1936 with treaties of friendship between Germany and Italy and between Germany and...

 military commands as to the location of the expected Allied assault across the Mediterranean and divert attention and resources from Sicily. It specifically indicated an invasion through the Balkans

Balkans

The Balkans is a geopolitical and cultural region of southeastern Europe...

, by use of bogus troop movements, radio traffic, recruitment of Greek interpreters, acquisition of Greek maps and Operation Mincemeat

Operation Mincemeat

Operation Mincemeat was a successful British deception plan during World War II. As part of the widespread deception plan Operation Barclay to cover the intended invasion of Italy from North Africa, Mincemeat helped to convince the German high command that the Allies planned to invade Greece and...

, the planting of false Allied plans.

The Allies created a sham army, the "Twelfth Army", in the eastern Mediterranean

Mediterranean Sea

The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

, which consisted of 12 fictitious divisions. Hitler

Adolf Hitler

Adolf Hitler was an Austrian-born German politician and the leader of the National Socialist German Workers Party , commonly referred to as the Nazi Party). He was Chancellor of Germany from 1933 to 1945, and head of state from 1934 to 1945...

 had suspected that the Allies would invade Europe through the Balkans and Barclay served to reinforce this opinion.

The deception was successful. The German High Command (Oberkommando der Wehrmacht

Oberkommando der Wehrmacht

The Oberkommando der Wehrmacht was part of the command structure of the armed forces of Nazi Germany during World War II.- Genesis :...

 - OKW), assumed a much greater concentration of Allied forces in the eastern Mediterranean than was the case and held to this assessment, making subsequent deceptions more credible. German forces in the Balkans were reinforced from eight to eighteen divisions. In addition, the Balkan threat diverted the Italian fleet into the Adriatic

Adriatic Sea

The Adriatic Sea is a body of water separating the Italian Peninsula from the Balkan peninsula, and the system of the Apennine Mountains from that of the Dinaric Alps and adjacent ranges...

, away from Sicily. Operation Husky

Allied invasion of Sicily

The Allied invasion of Sicily, codenamed Operation Husky, was a major World War II campaign, in which the Allies took Sicily from the Axis . It was a large scale amphibious and airborne operation, followed by six weeks of land combat. It launched the Italian Campaign.Husky began on the night of...

thus achieved surprise.