The 1st Division, nicknamed "Thunderbolt", was an

infantry Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadl ...

division in the

Irish Army The Irish Army () is the land component of the Defence Forces (Ireland), Defence Forces of Republic of Ireland, Ireland.The Defence Forces are made up of the Permanent Defence Forces – the standing branches – and the Reserve Defence Forces. ...

during the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. The division was one of two infantry divisions established by

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

during the duration of the war. The authorisation for the creation of the division, along with the 2nd Division, was granted by

Minister for Defence Minister may refer to: * Minister (Christianity), a Christian cleric ** Minister (Catholic Church) * Minister (government), a member of government who heads a ministry (government department) ** Minister without portfolio, a member of government w ...

Oscar Traynor Oscar Traynor (21 March 1886 – 14 December 1963) was an Irish republican and Fianna Fáil politician who served as Minister for Justice from 1957 to 1961, Minister for Defence from 1939 to 1948 and 1951 to 1954, Minister for Posts and Telegr ...

on the 9th of May, 1941 as part of military expansion. The division was headquartered at

Collins Barracks, Cork Collins Barracks () is a military barracks on the Old Youghal Road on the north side of Cork in Ireland. Originally serving as a British military barracks from the early 19th century, it was handed-over to the Irish military following the I ...

as part of the Southern Command.

Origins

Following the declaration of state emergency by the de Valera government in 1939, efforts were made for military expansion. However, there was no grave concern until the

Fall of France The Battle of France (; 10 May – 25 June 1940), also known as the Western Campaign (), the French Campaign (, ) and the Fall of France, during the Second World War was the German invasion of the Low Countries (Belgium, Luxembourg and the Net ...

in 1940, after which the neutral status of Ireland was in peril. Prior to the outbreak of war in December 1937, it was estimated that a force of three divisions would be necessary to defend Ireland in the event of an invasion. However, by September 1939, only two reinforced

brigade A brigade is a major tactical military unit, military formation that typically comprises three to six battalions plus supporting elements. It is roughly equivalent to an enlarged or reinforced regiment. Two or more brigades may constitute ...

s (gravely understrength) were raised. By early 1941, seven brigades were mobilised — just over 40,000 men. The question of divisions was put forth at the start of 1941, and so the decision to authorise the establishment of two divisions was given by

, then

on the 9th of May, 1941. Six of the brigades would be organised into two divisions, thus leaving an independent brigade (the 5th) to be subordinated to the Curragh Command.

Organisation

The division was organised as follows: * 1st Brigade, based in

Clonmel Clonmel () is the county town and largest settlement of County Tipperary, Republic of Ireland, Ireland. The town is noted in Irish history for its resistance to the Cromwellian conquest of Ireland, Cromwellian army which sacked the towns of Dro ...

** 10th (Uisneach) Infantry Battalion ** 13th (Connacht) Infantry Battalion ** 21st Infantry Battalion ** 1st Field Artillery Regiment ** 1st Motor Squadron * 3rd Brigade, based in

Cork "Cork" or "CORK" may refer to: Materials * Cork (material), an impermeable buoyant plant product ** Stopper (plug), or "cork", a cylindrical or conical object used to seal a container *** Wine cork an item to seal or reseal wine Places Ireland * ...

** 4th Infantry Battalion ** 19th Infantry Battalion ** 31st Infantry Battalion ** 3rd Field Artillery Regiment ** 3rd Motor Squadron * 7th Brigade, based in

Limerick Limerick ( ; ) is a city in western Ireland, in County Limerick. It is in the Provinces of Ireland, province of Munster and is in the Mid-West Region, Ireland, Mid-West which comprises part of the Southern Region, Ireland, Southern Region. W ...

** 9th (Desmond) Infantry Battalion ** 12th (Desmond) Infantry Battalion ** 15th Infantry Battalion ** 7th Field Artillery Regiment ** 7th Motor Squadron Each brigade also consisted of field companies of engineers, signals, supply & transport; a field medical company; and military police. In addition to these units, the division was given two Armoured Squadrons (which serviced armoured cars and light tanks) as well as several cyclist squadrons (for anti-paratrooper operations). Col. Michael J. Costello was promoted to Major General and appointed commander in May; a man reported to be a "down to earth soldier" and prepared his division to a high state of readiness. His division was, counterintuitively, not subordinated to the Southern Command (which was under the command of Col. J. Hanrahan). These regional commands, which had been supplemented with brigades before the divisional-level organisation, were given various battalions, mobile squadrons and static establishments (or garrison companies).

Unit History

Over the course of the war, the division was primarily training and garrisoning key areas in the south of Ireland. Large-scale field exercises, named the Blackwater Exercises were held in the August and September 1942, when the 1st Division engaged the 2nd Division in various attack and defence exercises. Over 20,000 troops and 1,500 vehicles partook in the exercises — the largest manoeuvres ever undertaken by the Irish Defence Forces. The results were satisfactory, with drawbacks including the area of supply — remedied by further training in this area. To quote Maj. Gen. Costello:

Given the inadequate armament and signal equipment of the Forces, training concentrated on attaining superiority over a potential invader in night operations with small forces expected to yield capture of enemy arms and ammunition, in cross country mobility and in marksmanship and the use of mines and explosives generally. The platoons made silent advances during dark nights over difficult and unknown country.

Despite rather poor pay and sub-par living conditions, morale remained high throughout the Emergency.

References

{{reflist Ireland in World War II Divisions of the Republic of Ireland