Adam Friedrich Bishop of Würzburg and Duke of Franconia agreed to raise two infantry regiments to serve with the Austrian army fighting Frederick the Great's Prussians during the Seven Years' War (1756-63). The 2nd of these regiments was the so-called "Blue" Regiment of Würzburg. The regiment began to be raised in late 1756 and by May 1757 two infantry battalions had been formed, each with 6 companies of fusiliers (136 men per company) and one company of grenadiers (100 men). In total the regiment enlisted 1,860 men.
The men wore white uniforms with blue cuffs and lapels, hence the name. Immediately after the regiment he joined the imperial brigade (of the Holy Roman Empire of the German Nation – Reich) of Major General Kolb and operated in Franconia. He received his baptism of fire in a skirmish with the Prussians losing 5 men. He was involved in operations in the area under considerable attrition, now having only 1,168 men, mainly due to the collapse of supplies.
The regiment took part in the battle of Rosbach (November 5, 1757) where Frederick the Great's small Prussian army crushed Marshal Soubis' twice the size of the Franco-German forces. The regiment fought exceptionally well holding its positions while the other friendly forces had fled. But he suffered significant losses losing almost 300 of his men. But soon it was reinforced and reached 1,323 men again.
The following year the regiment operated in Bohemia and Saxony where it again distinguished itself. In 1759 the regiment participated in the operations included in the force of the Austrian general Hadik. On March 31, however, the 1st Battalion was completely destroyed when it received a surprise attack by the Prussian cavalry. The friendly cavalry fled leaving the swept Würzburg men completely exposed. The 2nd Battalion was similarly destroyed on August 2, 1759.
Only the two grenadier companies of the regiment that had been detached from their respective battalions were saved and continued to fight and even distinguished themselves very well at the battle of Corbitz , on 21 September 1759. They fought well again at the Battle of Maxen where the Prussians were soundly defeated (2,000 dead and wounded, over 11,700 Prussian prisoners). The grenadier companies joined shortly afterwards with the remnants of the two battalions forming a new battalion of 825 men.
At the beginning of 1760 the battalion was disbanded and the regiment was reorganized with two - reduced battalions and the grenadiers - with a total strength of 956 men. The regiment fought in the battle of Strela (August 20, 1760) where it distinguished itself by fighting in the face of the Prussians and charging with the lance to the Dürenberg heights occupied by them. But the losses were significant. The two grenadier companies were disbanded and one was formed with the survivors.
After the defeat of the anti-Prussian forces in the particularly bloody battle of Torgau (November 3, 1760) the regiment retreated to Dresden. But due to the losses the men of the regiment joined the "Red" regiment of Würzburg, also an outstanding regiment of the Reich Army.