Seamus O'Donovan was a leading volunteer

Volunteer (Irish republican)

Volunteer, often abbreviated Vol., is a term used by a number of Irish republican paramilitary organisations to describe their members. Among these have been the various forms of the Irish Republican Army and the Irish National Liberation Army...

 in the Irish Republican Army

Irish Republican Army

The Irish Republican Army was an Irish republican revolutionary military organisation. It was descended from the Irish Volunteers, an organisation established on 25 November 1913 that staged the Easter Rising in April 1916...

.

A native of County Roscommon

County Roscommon

County Roscommon is a county in Ireland. It is located in the West Region and is also part of the province of Connacht. It is named after the town of Roscommon. Roscommon County Council is the local authority for the county...

, he was an explosives expert and reputedly invented the "Irish Wallflower" and "Irish Cheddar" devices. He subsequently became IRA Director of Chemicals in 1921. During the Irish War of Independence

Irish War of Independence

The Irish War of Independence , Anglo-Irish War, Black and Tan War, or Tan War was a guerrilla war mounted by the Irish Republican Army against the British government and its forces in Ireland. It began in January 1919, following the Irish Republic's declaration of independence. Both sides agreed...

 he was imprisoned in Mountjoy and Kilmainham prisons and later interned in Newbridge, County Kildare.http://www.ucd.ie/archives/html/collections/odonovan-james.html

He opposed the Anglo-Irish Treaty

Anglo-Irish Treaty

The Anglo-Irish Treaty , officially called the Articles of Agreement for a Treaty Between Great Britain and Ireland, was a treaty between the Government of the United Kingdom of Great Britain and Ireland and representatives of the secessionist Irish Republic that concluded the Irish War of...

 and fought in the Irish Civil War

Irish Civil War

The Irish Civil War was a conflict that accompanied the establishment of the Irish Free State as an entity independent from the United Kingdom within the British Empire....

.

In 1938, at the request of IRA chief of staff Seán Russell

Seán Russell

Seán Russell was an Irish republican who held senior positions in the IRA until the end of the Irish War of Independence...

, he wrote the S-Plan

S-Plan

The S-Plan or Sabotage Campaign or England Campaign was a campaign of bombing and sabotage against the civil, economic, and military infrastructure of the United Kingdom from 1939 to 1940, conducted by members of the Irish Republican Army . It was conceived by Seamus O'Donovan in 1938 at the...

, a bombing campaign targeting England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

.

Involvement with Abwehr (German Intelligence)

As "Agent V-Held", he visited Germany three times in 1939 on behalf of the IRA.http://homepage.tinet.ie/~eirenua/may97/50yrsago.htm

On 28 February he negotiated an arms and radio equipment delivery at the Abwehrstelle in Hamburg. On 26 April he concluded a new arms deal with the Abwehrstelle and established with the help of a Breton a secret courier connection to Ireland via France. On 23 August, O'Donovan received the last instructions for the event of war.http://forum.panzer-archiv.de/viewtopic.php?p=93324&sid=b76c64dd9815dfe7a65d584d3c7c6397

On 9 February 1940, Abwehr

Abwehr

The Abwehr was a German military intelligence organisation from 1921 to 1944. The term Abwehr was used as a concession to Allied demands that Germany's post-World War I intelligence activities be for "defensive" purposes only...

 II agent Ernst Weber-Drohl landed at Killala Bay

Killala Bay

Killala Bay is a bay on the west coast of Ireland between County Mayo and County Sligo. It is situated between Lenadoon Point and Downpatrick Head and is the estuary for the River Moy....

, County Sligo aboard U-37. He was equipped with a 'Ufa' transmitter, cash, and instructions for O'Donovan who by this time was the chief IRA contact for Abwehr I/II. The transmitter was lost upon landing, but when Weber-Drohl reached O'Donovan, 100 miles inshore at Shankill

Shankill

Shankill can mean:* Belfast Shankill * Belfast Shankill , the 1918–1922 UK Parliament constituency* Shankill, County Antrim, a parish in County Antrim, Northern Ireland...

, Killiney

Killiney

Killiney is a suburb of Dublin in south County Dublin, Ireland. It is within the administrative area of Dún Laoghaire-Rathdown County. The area is by the coast, south of neighbouring Dalkey, and north to Shankill area in the most southern outskirt of Dublin....

, County Dublin

County Dublin

County Dublin is a county in Ireland. It is part of the Dublin Region and is also located in the province of Leinster. It is named after the city of Dublin which is the capital of Ireland. County Dublin was one of the first of the parts of Ireland to be shired by King John of England following the...

, he was able to deliver new transmission codes, $14,450 in cash, and a message from "Pfalzgraf Section" asking that the IRA concentrate its S-Plan attacks on military rather than civilian targets.

In 1940, he was involved in setting up Córas na Poblachta

Córas na Poblachta

Córas na Poblachta , abbreviated CnaP, was a minor Irish republican political party founded in 1940.-Origins:The idea for a new party was discussed at a meeting in Dublin on February 21, 1940 attended by 104 former officers of the pro- and anti-Treaty wings of the Irish Republican Army. The...

, a party which proved unsuccessful.