Information:  - Sulpicius Alexander ( fl . late fourth century ) was a Roman historian of Germanic tribes . His work is lost , but his Historia in at least four books is quoted by Gregory of Tours . It was perhaps a continuation of the Res gestae by Ammianus Marcellinus ( which ended in 378 AD ) and dealt with events at least until the death of Valentinian II ( 392 AD ) . The work of Sulpicius Alexander as extracts in Gregory 's Decem Libri Historiarum ( II 9 ) is considered an important source in any discussion of the origin of the Frankish tribes .  - The Nuclear Engine for Rocket Vehicle Application (NERVA) was a U.S. nuclear thermal rocket engine development program that ran for roughly two decades. NERVA was a joint effort of the U.S. Atomic Energy Commission (AEC) and NASA, managed by the Space Nuclear Propulsion Office (SNPO) until both the program and the office ended at the end of 1972.  - Valentinian II (371  15 May 392), was Roman Emperor from AD 375 to 392.  - Ammianus Marcellinus (born c. 325330 died c. 391400) was a Roman soldier and historian who wrote the penultimate major historical account surviving from Antiquity (preceding Procopius). His work, known as the Res Gestae, chronicled in Latin the history of Rome from the accession of the emperor Nerva in 96 to the death of Valens at the Battle of Adrianople in 378, although only the sections covering the period 353378 survive.  - St. Martin of Tours (316 or 336  8 November 397) was Bishop of Tours, whose shrine in France became a famous stopping-point for pilgrims on the road to Santiago de Compostela in Spain. He has become one of the most familiar and recognizable Christian saints, sometimes venerated as a military saint. As he was born in what is now Szombathely, Hungary, spent much of his childhood in Pavia, Italy, and lived most of his adult life in France, he is considered a spiritual bridge across Europe.  - Valentinian I (3 July 321  17 November 375), also known as Valentinian the Great, was Roman emperor from 364 to 375. Upon becoming emperor he made his brother Valens his co-emperor, giving him rule of the eastern provinces while Valentinian retained the west.  - Procopius of Caesarea (; 500  554 AD) was a prominent late antique scholar from Palaestina Prima. Accompanying the Roman general Belisarius in the wars of the Emperor Justinian, he became the principal Byzantine historian of the 6th century, writing the "Wars" (or "Histories"), the "Buildings of Justinian" and the now-celebrated (and infamous) "Secret History". He is commonly held to be the last major historian of the ancient Western world.  - The Battle of Adrianople (9 August 378), sometimes known as the Battle of Hadrianopolis, was fought between an Eastern Roman army led by the Eastern Roman Emperor Valens and Gothic rebels (largely Thervings as well as Greutungs, non-Gothic Alans, and various local rebels) led by Fritigern. The battle took place about north of Adrianople (modern Edirne in European Turkey, near the border with Greece and Bulgaria) in the Roman province of Thracia. It ended with an overwhelming victory for the Goths and the death of Emperor Valens.  - Gaul (Latin: "Gallia") was a region of Western Europe during the Iron Age that was inhabited by Celtic tribes, encompassing present day France, Luxembourg, Belgium, most of Switzerland, Northern Italy, as well as the parts of the Netherlands, Central Italy and Germany on the west bank of the Rhine. It covered an area of 190,800 mi² or 494,169 km². According to the testimony of Julius Caesar, Gaul was divided into three parts: Gallia Celtica, Belgica and Aquitania. Archaeologically, the Gauls were bearers of the La Tène culture, which extended across all of Gaul, as well as east to Raetia, Noricum, Pannonia and southwestern Germania during the 5th to 1st centuries BC. During the 2nd and 1st centuries BC, Gaul fell under Roman rule: Gallia Cisalpina was conquered in 203 BC and Gallia Narbonensis in 123 BC. Gaul was invaded after 120 BC by the Cimbri and the Teutons, who were in turn defeated by the Romans by 103 BC. Julius Caesar finally subdued the remaining parts of Gaul in his campaigns of 58 to 51 BC.  - Valens (328  9 August 378), fully "Flavius Julius Valens Augustus", was Eastern Roman Emperor from 364 to 378. He was given the eastern half of the empire by his brother Valentinian I after the latter's accession to the throne. Valens, sometimes known as the Last True Roman, was defeated and killed in the Battle of Adrianople, which marked the beginning of the collapse of the decaying Western Roman Empire.  - Saint Gregory of Tours (30 November c. 538  17 November 594) was a Gallo-Roman historian and Bishop of Tours, which made him a leading prelate of Gaul. He was born Georgius Florentius, later adding the name Gregorius in honour of his maternal great-grandfather. He is the main contemporary source for Merovingian history. His most notable work was his "Decem Libri Historiarum" or "Ten Books of Histories," better known as the "Historia Francorum" ("History of the Franks"), a title given to it by later chroniclers, but he is also known for his accounts of the miracles of saints, especially four books of the miracles of Martin of Tours. St Martin's tomb was a major draw in the 6th century, and Gregory's writings had the practical aspect of promoting this highly organized devotion.  - The Franks (or ') are historically first known as a group of Germanic tribes that inhabited the land between the Lower and Middle Rhine in the 3rd century AD, and second as the people of Gaul who merged with the Gallo-Roman populations during succeeding centuries, passing on their name to modern-day France and becoming part of the heritage of the modern French people. Some Franks raided Roman territory, while other Frankish tribes joined the Roman troops of Gaul. In later times, Franks became the military rulers of the northern part of Roman Gaul. With the coronation of their ruler Charlemagne as ' by Pope Leo III in 800 AD, he and his successors were recognised as legitimate successors to the emperors of the Western Roman Empire.  - The Roman emperor was the ruler of the Roman Empire during the imperial period (starting in 27 BC). The emperors used a variety of different titles throughout history. Often when a given Roman is described as becoming "emperor" in English, it reflects his taking of the title "Augustus" or "Caesar". Another title often used was "imperator", originally a military honorific. Early Emperors also used the title "princeps" (first citizen). Emperors frequently amassed republican titles, notably "Princeps Senatus", "Consul" and "Pontifex Maximus".    Given the paragraphs above, decide what entity has the relation 'date of birth' with '400'.
sulpicius alexander