The federal eagle is one of Germany's three state symbols and has its roots in the Holy Roman Empire. As far back as 104 BC, the consul Gaius Marius designated the eagle as a standard for the legions, and throughout history, it has represented a divine emblem for kings and emperors. In 1433, German emperors began using the eagle, and after the former Holy Roman Empire fell apart, the Holy Roman Empire of the German Nation inherited the symbol. German emperors were reserved the double-headed eagle, while German kings were associated with the regular eagle.
During the German Revolution of 1848/49, the St. Paul's church assembly selected the double-headed eagle as their new coat of arms to align with the Holy Roman Empire of the German Nation. However, despite their efforts, the revolution failed, and both the black, red, and gold flag and the coat of arms of 1848 were discarded. Later, in 1871, the single-headed eagle became the coat of arms of the newly formed German Reich, connecting to the Prussian tradition.
The federal eagle appears in various forms, but the heraldic rules dictate that the eagle's head must face to the right (as depicted in the image above) and not have a crown. Additionally, the federal eagle must be levitating in the shield. The Federal Eagle is protected by law, which forbids the use of the state symbol in any form other than for official purposes, art, or education. This law extends to flags featuring the eagle; only institutions representing the German government may hoist a flag with an eagle on it.