SARATOGA SPRINGS, N.Y. -- When the U.S. Army launched the first American-planned and -led battle of World War I on Sept. 12, 1918, the 42nd Division was on the leading edge of the attack.

The Battle of Saint-Mihiel was the first time in WWI that an American Army went into the attack on its own. It was the first time an American Army staff drafted a battle plan for the war.

That plan featured air support from 1,481 American, French and British planes. Also in the plan was the first American tank attack ever, with 144 tanks led by Lt. Col. George S. Patton, attacking in support of the 42nd Division.

The 42nd Division was nicknamed the "Rainbow Division" because it was made up of National Guard units from 26 states. The division stretched across the country "like a rainbow" according to its Chief of Staff, Col. Douglas MacArthur.

The New York National Guard had contributed its famous "Fighting 69th Irish" Regiment to the division. Re-numbered the 165th Infantry Regiment, the New Yorkers, along with regiments from Alabama, Iowa and Ohio, were the core of the division's fighting power.

The 42nd Division had fought as part of a French army. Now it was going to fight as part of an American Army.

For the first American offensive, Gen. John J. Pershing, the American commander, proposed attacking the Saint-Mihiel salient, a triangular piece of terrain which cut one French railroad line and allowed German artillery to fire on another.

The salient, a German outpost jutting into French lines, took its name from the almost destroyed village at the peak of the triangle. Taking the Saint-Mihiel salient would secure rail lines the Americans needed to conduct future attacks. However, the Germans had fortified the region with dugouts and machine gun nests.

Pershing moved units into the woods before the position at night and planned a massive artillery barrage to launch the attack.

He had 13 American divisions -- twice as large as other English or French divisions -- and four French divisions to attack eight German divisions. There were 450,000 Americans and 110,000 French and French colonial troops -- Soldiers from France's African colonies -- ready to attack.

The 42nd Division was part of the American 4th Corps. The corps attacked across the Woerve Plain against the southwestern face of the German position. The 42nd was in the middle of the corps line, with the 89th and 1st Divisions on its flanks.

The 42nd Division's two brigades, the 83rd Infantry Brigade and the 84th Infantry Brigade, attacked with two Infantry battalions up front, each followed by a battalion in support and a third battalion in reserve.

The 1st Battalion of the 165th Infantry, led by newly promoted Lt. Col. William " Wild Bill" Donovan, led the attack in the 165th sector. The unit had taken heavy casualties in earlier fighting, and many of Donovan's men were replacements.

The American artillery bombardment started at 1 a.m. on Sept. 12. At 5 a.m., 165th Infantry and the rest of the 42nd Divisions advanced. What the American Soldiers found were Germans falling back as quickly as they could.

German commanders realized an attack was coming and they decided they could no longer hold the high ground above the Meuse. They had been pulling troops back when the 42nd Division and other American units attacked.

At the village of Maizeray, Donovan took 30 men and outflanked a German position that was putting up a fight, forcing the enemy to surrender. The New York regiment reached its objectives for the first day by 2 p.m.

The New Yorkers were amazed to find German dugouts with running water, electricity, and dining and recreation areas.

Over the next two days the Americans continued to attack. The 165th Infantry Regiment advanced 11 miles, retook five French villages and captured 350 German soldiers.

On Sept. 14, 1918 the 42nd Division was ordered onto the defensive to prepare for a German counterattack. The men patrolled and watched the front.

The Battle of Saint-Mihiel officially ended on Sept. 16.

The American First Army took 15,000 German soldiers prisoner, captured 257 guns, and eliminated a German position, which had been there since 1914.

The 42nd Division lost 234 killed and 659 wounded and missing during the battle. The 165th's losses were 125 wounded and 35 killed in action, with 12 dying of their wounds.

Pershing began to move units for the next big battle, an attack into the Argonne region, but the 42nd Division stayed in position on the defensive.

On Sept. 23, the 165th was ordered to conduct a raid as part of a series of demonstrations designed to distract the German leaders before the massive Meuse-Argonne attack.

American artillery opened up on the Germans at 1 a.m. and stopped at 7 a.m. Then the 1st and 2nd Battalions of the New York National Guard Regiment attacked.

In the words of Martin Hogan, one of the Soldiers in the attack, the 165th Soldiers "ran over the first opposition before the enemy had opportunity to catch its breath after the terrors of the tremendous battering by our guns.

"They continued to overrun all opposition throughout the day, to romp over the nerve-shattered and demoralized Germans," he wrote.

The Americans found plenty of souvenirs in the German lines and returned to their positions loaded down with German pistols, rations, and medals, Hogan reported.

On Sept. 30 the 42nd Division was pulled out of the line and replaced by the 89th Division.

Now the Rainbow Division would enter the biggest American battle of all time, the Meuse-Argonne Offensive, along with 1.2 million other American Soldiers.

Editor's note: During the World War I centennial observance, the Division of Military and Naval Affairs will be issuing press releases noting key dates, which impacted New Yorkers, based on information provided by the New York State Military Museum in Saratoga Springs, N.Y. More than 400,000 New Yorkers served in the military during World War I -- more than any other state.