Sentenced to death for high treason, he was transported to Tasmania, escaped to become a US celebrity, fought Indians in the Wild West and led a brigade of renowned 'shock' troops in the American civil war before, some believe, being murdered by his enemies.

Rebel Thomas Francis Meagher, the man who created the Irish national flag, lived a high-octane life.

Following his dramatic escape from Tasmania, the twice-married Waterford adventurer qualified as a lawyer in New York, established a newspaper and was promoted to the rank of brigadier general in the Union army, where he earned a reputation as the inspirational leader of its most famous unit.

He eventually became acting governor of the then-frontier state of Montana, before mysteriously falling overboard from a steamer on the Missouri river and drowning at the age of 44.

Now, nearly 150 years after his death, this enormously colourful patriot is to be the central figure in a two-part television documentary by Dublin-based film company Tile Films, which will be broadcast in Ireland and the US this month.

Born in 1823 to an affluent merchant Catholic family, Meagher's father was not only a supporter of Daniel O'Connell and Catholic emancipation and an MP for Waterford, but the city's first Catholic Lord Mayor for 200 years.

Meagher showed an early tendency to get into scrapes. As a student at Clongowes Wood, he was asked to leave the college after swimming across the Liffey to go for a night's drinking. He was then sent to Stonyhurst, a prestigious Catholic college in the UK.

After finishing his education in England, he returned home and became involved with the Young Ireland nationalist movement.

In 1846, in response to an attempt by Daniel O'Connell to gain a pledge of non- violence to the British government, he gave his famous 'Sword Speech', condoning violence as a last resort in the campaign for Irish freedom.

"Meagher's stance was that if Britain was not prepared to concede freedom to Ireland under any circumstances, then violence could be necessary," says John Hearne, co-author of 'Thomas Francis Meagher: the Making of an Irish American'.

The resourceful 20-something even sailed to France in 1848, seeking military support for a planned Young Ireland uprising, but was unsuccessful.

However, while in France, he witnessed the unifying effect of the French flag on the populace and felt Ireland needed a similar unifying symbol -- so he created one.

"The tricolour concept had been around for many years -- it was usually worn as a button or as a sash by supporters of O'Connell," says Hearne.

"However, it was not then regarded as a national symbol. Meagher recognised the potential of the tricolour as both a national symbol and a unifying force between Catholics and Protestants in Ireland."

Later, Meagher's memory proved to be an inspiration for the leaders of the 1916 Rising, and in 1937 his tricolour was adopted as the national flag.

However, such glory was still a long way away in July 1848, when a revolt by a radical wing of the Young Irelanders in Ballingarry, Co Tipperary, was suppressed. Meagher was arrested, tried for high treason together with a number of Young Ireland leaders, and sentenced to death.

The sentence was later commuted to transportation for life following representations by his influential family, and, in July 1849, Meagher was sent to Van Diemen's Land, now known as Tasmania.

It wasn't a conventional prison sentence, explains IFTA-nominated director Keith Farrell of Tile Films.

"Because Meagher was a gentleman he was allowed out and about in Tasmania, and, during his 'jail term', even courted and married the daughter of an Irish settler family there, Catherine Bennett."

However, in 1852 he escaped Tasmania, leaving his pregnant wife behind. He was picked up by a ship waiting off the coast of Tasmania and brought to America, arriving four months later to a hero's welcome in New York.

According to Hearne, he is one of the few convicts who ever successfully escaped from Tasmania.

"Here was a man who had rebelled against the British forces, had escaped a death sentence, was transported to Tasmania -- and escaped again. He was seen as a real hero and patriot by the Irish-American community," adds Farrell.

For the next 10 years, Meagher was a newspaper publisher -- he founded the 'Irish News' -- a lawyer, public speaker and celebrity, and he also ran two expeditions to Central America, exploring the region for commercial possibilities.

His wife Catherine, still in Tasmania, had their baby -- which died at the age of four months -- and later travelled to Ireland. The couple were eventually reunited in New York. However, Catherine later returned to Waterford and had a second son by Meagher. She died aged just 23 in May 1854.

Two years later, Meagher married again -- this time to Elizabeth Townsend, daughter of a wealthy New York steel and railroad family. The Townsends were elite Wasps and disliked Meagher, who was to them an escaped Catholic convict.

By the time the civil war began in April 1861 Meagher was an American citizen, an acknowledged Irish-American leader and one of the most famous Irishmen of his time in the US.

When the war began, he rose to the Union cause and joined the 69th New York Militia, an Irish-American volunteer regiment. He was commissioned a captain and took part in the first major battle of that war in July 1861 at Bull Run.

Meather's response to the crushing defeat at Bull Run was to suggest the creation of an Irish brigade. Along with other members of the Irish-American community, he recruited three regiments and returned to the war front in northern Virginia, leading what was now known as the Irish Brigade.

"He wanted a distinctly Irish unit on the battle field," says Farrell, whose forthcoming two-part documentary, 'Fág an Bealach' (Clear the Way), covers the story of the Irish Brigade.

In February 1862, Meagher was made brigadier general, despite having no military experience. "He was a political general, but he had excellent officers below him who had served in the British and Austro-Hungarian and Papal armies," says Farrell, who adds that Meagher led from the front in most battles and was recognised as an inspiring leader.

The Irish Brigade fought with distinction and its members quickly earned themselves a reputation as the shock troops of the Union army.

The brigade suffered heavy losses, particularly at Antietam in September 1862, where their courage made them a household name across America.

Explains Farrell: "The Irish Brigade attacked an enemy position and stayed until the enemy lines were fatally weakened and the brigade's reinforcements were able to push through."

Further losses were experienced at Fredericksburg, Virginia, that December, where 14,000 union soldiers died. "Meagher and his men had to attack a low hill called Maryes Heights. The Confederates were well protected behind a wall. The Irish got closer to the enemy than anyone else but were driven back," says Farrell.

"Meagher, who had been ordered to climb the hill on foot alongside his men, went back for his horse. By the time he returned the whole brigade had been almost wiped out. He was devastated by this and today you would say he suffered from shell shock as a result."

By now the Irish Brigade, originally 3,000 strong, was reduced to fewer than 500 men, and Meagher tried to convince the authorities to withdraw it from active service in order to regroup and recruit. "He even went to President Lincoln to ask for furlough, but was turned down," says Farrell.

Disappointed and furious, he tendered his resignation as brigadier general in May 1863 and it was accepted. "I think he didn't believe that they would accept his resignation -- he was trying to force their hand -- but, at this stage, the army was not granting anybody furlough and the Irish, though far diminished in number, were still seen as an effective fighting force.

"He retired to New York a changed man. He had seen the horror of war face-on and I think it revolted him," Farrell comments.

The new documentary series follows the untold story of how the men of the Irish Brigade sacrificed their lives on the bloody battlefields of the war. Filmed on location in both the US and Ireland, it re-enacts the adventure, and the ultimate victory of the Irish Brigade through large-scale dramatic reconstructions, created with leading US re-enactment company Historical Entertainment.

"The brigade continually distinguished itself in combat. Stories of the brigade's successes raised the profile of the Irish in America and became a source of pride for the downtrodden Irish-American community," says Farrell.

After much campaigning to the war department, Meagher returned to active service some months later. He was given command of a garrison brigade in Tennessee, where he was responsible for protecting railway lines from the Confederate army.

He managed this successfully, but his subsequent, embarrassingly mismanaged transfer of injured troops to Carolina saw him sent back to New York. Meagher's increasing reputation as a hard drinker probably influenced this decision, says Hearne.

However, his strong political connections still held true, and when Lincoln was assassinated, he was a member of the Honour Guard of army generals who stood in attendance around the dead president's open coffin.

After the war, his stock was at an all-time low. He sought an official appointment from the new administration under President Andrew Johnson, and even travelled to Minnesota to seek out opportunities himself.

While there, he was notified of his appointment as secretary for the territory of Montana, which was still a wild frontier. On arrival, he became the acting governor and threw himself into his law and order duties, which included fighting the local Blackfeet and Crow Indians.

On July 1867, while on a tour of duty connected with the Indian campaign the 44-year-old fell overboard from a steamer and drowned.

"His supporters and friends argued that he had been murdered by his enemies," says Farrell, who points out that not only did Meagher have political enemies among local Republicans, but his initiative to encourage Irish settlers to come to Montana was highly unpopular.

However he died, Meagher's legacy is a glorious one, says Hearne. "This was a highly intelligent man, who was brave and impetuous. He managed to consolidate the Irish population in America into a potent political force."

When President John F Kennedy visited Ireland in 1963, he credited Meagher with being the Irishman who first opened the door through which Kennedy accessed the highest office of power in the land.

'Fag an Bealach' will be aired on TG4 on March 23

Weekend Magazine