Rhine river in the context of "Borders of the Roman Empire"

The Franks (Latin: Franci or gens Francorum; German: Franken; French: Francs) were originally a group of Germanic peoples who lived near the Rhine-river military border of Germania Inferior, which was the most northerly province of the Roman Empire in continental Europe. These Frankish tribes lived for centuries under varying degrees of Roman hegemony and influence, but after the collapse of Roman institutions in western Europe, they took control of a large empire including areas that had been ruled by Rome, and what it meant to be a Frank began to evolve. Once they were deeply established in Gaul, the Franks became a multilingual, Catholic Christian people, who subsequently came to rule over several other post-Roman kingdoms both inside and outside the old empire. In a broader sense, much of the population of western Europe could eventually be described as Franks in some contexts.

The term "Frank" itself first appeared in the 3rd century AD, during the crisis of the 3rd century – a period when Rome lost control of regions near the lower Rhine. In the 4th century, Roman authors also began to use another new collective term for enemy tribes in the lower Rhine, "Saxons". Although the Saxons and Franks were later more clearly distinguished, there are signs that the terms Frank and Saxon were not always mutually exclusive at first. Over centuries, the Romans recruited large numbers of Frankish soldiers, some of whom achieved high imperial rank. Already in the 4th century, Franks were living semi-independently in parts of Germania Inferior. The Roman administration of Britain and northern Gaul once again began to break down, and in about 406 it was the Franks who attempted to defend the Roman border when it was crossed by Alans and Vandals from eastern Europe. Frankish kings subsequently divided up Germania Inferior between them, and at least one, Chlodio, also began to rule more Romanized populations to the south, in what is now northern France. In 451, Frankish groups participated on both sides in the Battle of the Catalaunian Plains, where Attila and his allies were defeated by a Roman-led alliance of various peoples established in Gaul.

The Principality of Birkenfeld (German: Fürstentum Birkenfeld), known after 1919 as the Region of Birkenfeld (German: Landesteil Birkenfeld), was an exclave of the Grand Duchy and then the Free State of Oldenburg from 1817 until 1937, when it was incorporated into Prussia. It was located in the Nahe region on the left bank of the Rhine river and its capital was Birkenfeld. The government was led by a Government-President (Regierungspräsident) who was appointed by the government of Oldenburg.

The Franks (Latin: Franci or gens Francorum; German: Franken; French: Francs) were originally a group of Germanic peoples who lived near the Rhine-river military border of Germania Inferior, which was the most northerly province of the Roman Empire in continental Europe. The original Frankish language was West Germanic. These Frankish tribes lived for centuries under varying degrees of Roman hegemony and influence, but after the collapse of Roman institutions in western Europe, they took control of a large empire including areas that had been ruled by Rome, and what it meant to be a Frank began to evolve. Once they were deeply established in Gaul, the Franks became a multilingual, Catholic Christian people, who subsequently came to rule over several other post-Roman kingdoms both inside and outside the old empire. In a broader sense, much of the population of western Europe could eventually be described as Franks in some contexts.

The term "Frank" itself first appeared in the 3rd century AD, during the crisis of the 3rd century – a period when Rome lost control of regions near the lower Rhine. In the 4th century, Roman authors also began to use another new collective term for enemy tribes in the lower Rhine, "Saxons". Although the Saxons and Franks were later more clearly distinguished, there are signs that the terms Frank and Saxon were not always mutually exclusive at first. Over centuries, the Romans recruited large numbers of Frankish soldiers, some of whom achieved high imperial rank. Already in the 4th century, Franks were living semi-independently in parts of Germania Inferior. The Roman administration of Britain and northern Gaul once again began to break down, and in about 406 it was the Franks who attempted to defend the Roman border when it was crossed by Alans and Vandals from eastern Europe. Frankish kings subsequently divided up Germania Inferior between them, and at least one, Chlodio, also began to rule more Romanized populations to the south, in what is now northern France. In 451, Frankish groups participated on both sides in the Battle of the Catalaunian Plains, where Attila and his allies were defeated by a Roman-led alliance of various peoples established in Gaul.