Lisa Smith has pleaded not guilty to charges of being a member of ISIS and of trying to finance terrorism.
The trial against the 39-year-old former Irish Defence Forces Dundalk member got underway at the Special Criminal Court today.
Ms Smith applied to be discharged from the army after ten years of service in 2011.
The court heard she had converted to Islam by then and an application to wear a hijab during duty was refused.
Through private Facebook chats, it is the prosecution’s case that she was mentored on certain aspects of Islamic faith.
The prosecuting barrister, Sean Gillane, claimed she discussed her wish to make Hijra, which was described as a call to followers to migrate to areas under ISIS control.
Mr Gillane described the answering of this call as a “central act of allegiance” to what he described as a “proto state.”
She is also accused of trying to finance the terrorist group through an €800 wire transfer that was stopped by authorities in May 2015.