In 1860, 1,400 Irishmen travelled to Italy in response to Pope Pius IX’s call for help in thwarting Italian efforts to seize Papal Lands.

Up to the mid-nineteenth century Italy was a patchwork of small independent states, each influenced to a degree by neighbouring super powers such as France and Austria. A uniformitarian movement took hold in the 1850’s, however, with Giuseppe Garibaldi and Giuseppe Mazzini included among its leaders. Key to their aims was the annexation of the Papal States, a vast territory interposed much like a wide band across the middle of the Italian peninsula. With no viable military force to protect his lands, an increasingly worried Pope Pius IX issued a call to Catholics throughout Europe for men and arms to raise an army in his defence.

By March 1860, Papal Emissaries had arrived in Dublin to recruit an Irish battalion to serve the Pope. At the forefront of this effort was an alliance between Count Charles McDonnell of Vienna, a ‘Chamberlain’ to the Pope, and Alexander Martin Sullivan, the Editor of the national newspaper. Within a matter of weeks, the resultant recruitment committee had organised rallies in support of the Pope throughout the country, and more than £80,000 was collected (equivalent to £5 million today), most of it channelled to the Vatican through the Irish Pontifical College in Rome. Sermons from the pulpits of parish churches also acted as conduits for the call to arms that emanated from St. Peter's Square.

Religion was not the sole motivation for the Irish volunteers. Their response was also against the anti-Catholic or anti-Papal elements within the British Establishment. In an effort to destabilise French and Austrian influence among the Italian states the government openly supported the reunification movement with support of the Royal Navy in southern Italy. The British government also introduced legislation – The Foreign Enlistment Act - which prohibited British citizens from joining foreign armies. The Irish Constabulary was charged with enforcing this act but, using their discretion, there was no will to enforce the Act. Indeed a large number of members of the Force resigned their positions and travelled to Italy to join the Papal army. These were trained men and were an invaluable asset to the new army. Records show that a body of 20 men resigned from the Cork force to join the Papal army. Often, the young volunteers travelled as pilgrims to avoid a clash with the foreign Enlistment Act.

The recruits represented a range of trades in Ireland mostly from the predominately Catholic southern counties, fit young men intent on adventure. The reality proved to be somewhat different.

By late June 1860, the majority of the Irish battalion had gathered in Italy to begin a rushed form of training in the company of volunteers from nine further nationalities. To make matters worse, English was not among the three languages adopted by the Papal army. In command of the Irish unit, newly christened the Battalion of Saint Patrick, was County Louth native Major Myles O’Reilly.

General Louis Christophe Leon Juchault de Lamoriciere, a Frenchman, was the overall commander of the entire Papal Army. He was considered one of the finest soldiers in Europe and recently returned from active duty in Algeria with the French Foreign Legion.

Despite the quality of their commanders, the recently arrived Irish found the military organisation of this hastily convened army to be shambolic. With no military source for arms and uniforms, the Irish were poorly clothed, worse than any other nationality in the Papal army. They were issued with surplus Austrian uniforms left over from previous wars and obsolete, smooth–bore, muskets. The green uniforms, promised months before in Ireland, never arrived and this caused the most disappointment to the men as they had no badge identifying themselves as Irish. Furthermore, the Irishmen never served together and were split into companies, assigned to defend papal land in separate key locations. While a few hundred disgruntled individuals returned to Dublin, the Irish fighting spirit came to the fore among the 1,000 or so who remained. General Lamoriciere, who was quick to upbraid the slack units in his hodgepodge of an army, nonetheless had praise for his Irish recruits.