The files relate to Teresa Byrne’s application for a service pension and document her extensive nationalist activity from before 1916 through to the mid-1920s. She joined the Hibernian Rifles, based at 28 North Frederick Street, around 1914–1915, where she initially assisted men arriving from Scotland and England. Her father operated a small munitions factory on Phibsborough Road, and Teresa, along with her sister Cathleen Kavanagh, was actively involved in transporting munitions. 

During Easter Week 1916, she was mobilised and reported to St Stephen’s Green under Séamus Kavanagh, where she primarily carried ammunition and messages between positions. She later reported to Cumann na mBan and was assigned to Father Matthew Hall, assisting with cooking duties. Her father, Christopher Healy was a member of the Hibernian Rifles. Her brother Sean Healy was only 26 when he lost his life on 27 April after being wounded on Byrne's Corner, in Phibsborough. 

Between 1917 and 1919, she took part in fundraising and electioneering for the O’Rahilly Sinn Féin Club. At the same time, munitions production resumed at her father’s factory, and she helped transport arms and supplies by pony and cart between locations in Dublin. She also assisted in moving weapons for key individuals, including Séamus Robinson.

Throughout the War of Independence, she remained active in dispatching goods, weapons, and ammunition, while also working at the Court Laundry from 1919, carrying out her nationalist activities in her spare time. She formally joined the Central Branch of Cumann na mBan in late 1921 or early 1922, partly to avoid drawing attention to her ongoing work.

Her involvement continued until 1926, when her home was raided and her father arrested; 30,000 rounds of ammunition were discovered. The files also note the personal impact on her family: her husband, Thomas Byrne, a shipyard riveter, lost his employment, and together they had six children.