Final answer:
On 10 June 1190, Frederick Barbarossa drowned in the River Goksu, which impacted the Third Crusade by causing a leadership vacuum and decreasing morale.
Step-by-step explanation:
On 10 June 1190, at the River Goksu, Frederick Barbarossa, the Holy Roman Emperor, met his untimely death. While leading the Third Crusade, Frederick attempted to cross the river but tragically drowned. This event had a significant impact on the crusade as it created a leadership vacuum and decreased morale among Crusader forces.
Barbarossa's death influenced the crusade's dynamics, leaving his army to struggle without their charismatic leader, and many soldiers ultimately decided to return home rather than continue to the Holy Land without him.