Barry Keoghan as Cormac McDevitt in Rebellion. RTÉ Player RTÉ Player

LAST NIGHT’S EPISODE of Rebellion had a few people scratching their heads at one point.

As the rebels dug-in inside the GPO, they all stood up to sing a song that had a familiar tune but some not so familiar words.

It was most definitely the Irish national anthem. Except it wasn’t, because all the words were in English.

At best some people were confused, at worst people were annoyed.

But as you may know, and as many people pointed out online, it was entirely historically correct for the soldiers to be singing A Soldier’s Song in English.

The Irish language version wasn’t officially printed until 1923.

Specialist magazine History Ireland points out some of the facts about the song.

Written by Peader Kearney around 1907 with a melody by Patrick Heaney, it was printed in nationalist newspaper Irish Freedom in 1912. It then became a popular marching song for the Irish Volunteers in the years afterwards.

As the Trinity College Library points out, the song is known to have been sung at the GPO during the Easter Rising, so Rebellion weren’t making that up either.

In the years after the Rising, it was regularly sung in internment camps and its importance to volunteers began to grow.

Then, following the foundation of the Irish Free State, it continued to be used by the Free State Army.

(English language version, chorus from 0:40)

History Ireland says that Irish language translations of the song may have been written as early as 1917, but that it wasn’t officially published in Irish until 1923.

In November of that year, an Irish translation Amhrán na bhFiann first appeared in An t-Óglach, the Irish army journal.

The Irish language translation that became the dominant version of the song was translated by Liam Ó Rinn, who later became chief translator to the Oireachtas.

In terms of its adoption as the national anthem, it was a gradual process. In 1924 a number of competitions were established to select an anthem but they came to nothing.

Then in 1926, the Executive Council led by its President Willam Cosgrave selected A Soldier’s Song as the national anthem. It was played alongside the tricolour at the Dublin Horse Show that year.

It wasn’t until the 1930s that the Irish language version became widely sung as the national anthem.

Read: Bullets and burns were flying in last night’s action-packed episode of Rebellion >

Read: Rebellion’s Finnish director on criticism of the drama, and his bid to demystify 1916… >