In 1913 the regular local branch in that area was called simply ‘Sluagh Rathmines’ and Con Colbert was O/C.
In 1915 the Dublin Fianna was reorganized into a Battalion of nine companies and No. 4 Company was based at Ranelagh/Rathmines with Niall MacNeill (Eoin MacNeill’s son) as O/C.
Following Eoin MacNeill’s countermanding order, Niall MacNeill failed to mobilise in Easter week 1916 and was subsequently courtmartialed by Barney Mellows and Countess Markievicz for his ‘no-show’. He was exonerated and many at the time felt the court martial was just a ruse by GHQ to re-stamp their authority on Fianna Eireann following the disarray and disorganization in the aftermath of the Rising.
From May 1916 until June 1917 a minor re-organisation of the Fianna movement took place, No. 4 Company became No. 7 Company, which covered the Ranelagh and Rathmines area. Niall’s Cousin Hugo MacNeill was now O/C.
*(No. 4 by then was based in the Blackhall Street area)
A new Company was also formed in Rathfarnham, and was called No. 9 Coy. Niall MacNeill (apparently back in favour) took over this Company.
In June 1917 a more substantial re-organisation took place with the Dublin Brigade being organized into two Battalions (North and South Dublin). Garry Holohan was the overall Brigade Commandant. Barney Mellows, Hugo MacNeill and Joseph Reynolds commanded the South Dublin Battalion at various stages through the next four to five years.
By this stage the Company in the Ranelagh/Rathmines area (also covering Harold’s Cross) was known as ‘E’ Company and was part of the South Dublin Battalion. Between 1917 and 1920 the Captains of this ‘E’ Coy were T. Lee, D. MacNeill, P. Dunne and P. Dalton.
In January 1921, the Fianna organisation was re-organised to correspond with the IRA/Volunteers structure and the two existing Battalions (North and South Dublin) were formed into five Battalions (1st, 2nd, 3rd, 4th and 6th Battalions). The 3rd Battalion area covered Rathmines.
*The 5th Battalion of the IRA was an Engineers Battalion and the Fianna did not form a 5th Battalion. (Incidentally Fianna Officer Garry Holohan was also a Captain in the IRA’s 5th Battalion).
Most of the 3rd Battalion of Na Fianna Eireann took the Anti-Treaty side in the Civil War of 1922/23, as did most of the National Fianna organisation, with a few exceptions.