A letter written by President Abraham Lincoln, in the midst of the Civil War promoting several members of the Irish Brigade, is expected to fetch over $70,000 at auction this St. Patrick’s Day.

The letter, written on the president’s third to last birthday, Feb 12, 1863 is addressed to General Henry W Halleck. It discusses three soldiers of note in the famed Irish Brigade, an infantry brigade, consisting predominantly of Irish and Irish Americans, that served in the Union Army in the American Civil War.

Read more: The Irishman who captured Abraham Lincoln’s killer John Wilkes Booth

It reads:

“Gen. Meagher, now with me, says the Irish Brigade has had no promotion; and that Col. Robert Nugent & Col. Patrick Kelly, both of that Brigade have fairly earned promotion. They both hold commissions as Captains in the regular Army. Please examine these records with reference to the question of promoting one or both of them.”

Thomas Francis Meagher, who Lincoln was with when he wrote the letter, was born in The Mall, Waterford on August 23, 1823. In 1843 Meagher joined the Young Ireland movement, radical group which published The Nation and was committed to the overthrow of British rule in Ireland. Meagher was the first person in Ireland to raise the National flag, the Tricolor. This flag was then brought to Dublin prior to 1916 by Irish Volunteers from Waterford City.

Meagher was convicted of treason for his part in the 1848 Young Ireland rebellion and was exiled for life. He eventually found his way to America, where he served in the Union Army. He began raising troops as soon as the war began and soon found himself in charge of the Irish Brigade, which saw action at Bull Run, Antietam, and Fredericksburg.

Read more: Irish honor US Civil war hero at first 1916 Easter Rising commemoration event

Those mentioned in the letter were Brigadier General Robert Nugent and Patrick Kelly .

Nugent (June 27 1824 – June 20 1901) was an Irish-born US Army officer during the American Civil War and the Indian Wars. He was born in Kilkeel, County Down.

Kelly (c.1822 – June 16, 1864) was born in Castlehacket, Tuam, County Galway. He immigrated to the United States and started his American life in New York City. His wife Elizabeth was also from Tuam.

He led the famed Irish Brigade at the Battle of Gettysburg.

In fact, Meagher resigned his commission shortly after meeting with Lincoln. Kelly replaced him as commander and led the depleted Irish troops at the Battle of Gettysburg in July. Kelly was later killed in action during the Siege of Petersburg before ever officially being promoted. Nugent was the last commanding officer of the Irish Brigade, and was finally brevetted brigadier general until March 13, 1865.

It is estimated that 140,000 of the fighting men in the Union Army were Irish and played a significant role in the battle to stop disunion and end slavery. The Irish were awarded 11 medals of honor.

Read more: Ireland forgets Irish emigrants who fought in US Civil War

The heroic role of the Irish in the war has never been disputed. Abraham Lincoln once kissed an Irish battle flag, according to an officer present when the president visited George McClellan’s army at Harrison’s Landing, VA during the Civil War.

The Irish Brigade had fought so bravely that an officer reported the president picked up a corner of one of the Irish colors, kissed it and said, “God Bless the Irish Flag.” The incident was reported in The New York Times in the Opinionator column on the American Civil War by historian Terry L. Jones, author of six books on the Civil War.

Writing in The Times, Jones said that 140,000 Irish served on the side of the union, spread across 20 regiments.

“They fought so bravely, especially the Irish Brigade, that when General Edwin Sumner prepared for battle he would ask…“Where are my green flags?” and that he once swore that “if the Irishmen ever ran from the field he would have to run as well.”

Jones recounts how before every major battle Father William Corby, later President of Notre Dame, would ride down along the ranks of the brigade and give every man absolution. The motto on the flags of the Irish Brigade stated in Gaelic: “Who never retreated from the clash of spears” and the battle cry was “Fag an Bhealach” (“Clear the Way”).

Jones says the Irish Brigade’s bravery at Fredericksburg was unsurpassed.

He quotes The London Times correspondent William H. Russell (himself Irish-born) who wrote, “Never at Fontenoy, Albuera, or at Waterloo was more undaunted courage displayed by the sons of Erin than during those six frantic dashes which they directed against the almost impregnable positions of their foe.”

General Lee was said to have said, “Ah yes. That fighting 69th,” when he heard who was fighting so bravely on the other side. As a result, the “Fighting 69th” nickname stuck.

Speaking of the Lincoln letter up for auction on March 17, Robert Livingston, Executive VP at RR Auction called it “an excellent wartime letter by President Lincoln with a fine association to this well-known brigade.”

Also up for auction is a letter George Washington signed while president which discusses his disdain for those monetizing his likeness. That letter is expected to fetch $25,000+. A John Adams signed letter dealing with the constitution and powers of the presidency is also expected to sell for $25,000 or more.

The online bidding for the Presidential Collection of Everett Fisher from RR Auction began on March 10 and will conclude on March 17, 2016 at 7pm EDT.

For more information visit www.rrauction.com.

Photos courtesy of Sotheby's / Library of Congress.