Byzantine law was essentially a continuation of Roman law with increased Christian influence. Most sources define Byzantine law as the Roman legal traditions starting after the reign of Justinian I in the 6th century and ending with the Fall of Constantinople in the 15th century.
Though during and after the European Renaissance Western legal practices were heavily influenced by Justinian's Code (the Corpus Juris Civilis) and Roman law during classical times, Byzantine law nevertheless had substantial influence on Western traditions during the Middle Ages and after.
The most important work of Byzantine law was the Ecloga, issued by Leo III, the first major Roman-Byzantine legal code issued in Greek rather than Latin. Soon after the Farmer's Law was established regulating legal standards outside the cities. While the Ecloga was influential throughout the Mediterranean (and Europe) because of the importance of Constantinople as a trading center, the Farmer's Law was a seminal influence on Slavic legal traditions including those of Russia.
Byzantium inherited its main political, cultural and social institutions from Rome. Similarly, Roman law constituted the basis for the Byzantine legal system. For many centuries, the two great codifications of Roman law carried out by Theodosius II and Justinian respectively, were the cornerstones of Byzantine legislation. Of course, over the years these Roman codes were adjusted to the current circumstances and then replaced by new codifications, written in Greek. However, the influence of Roman law persisted, and it is obvious in codifications, such as Basilika, which was based on Corpus Juris Civilis. In the 11th century, Michael Psellos prides himself for being acquainted with the Roman legal legacy (" ").
In accordance with the late Roman legal tradition, the main source of law (fons legum) in Byzantium remained the enactments of the emperors. The latter initiated some major codifications of the Roman law, but they also issued their own "new laws", the Novels ("Novellae", ""). In early Byzantine (late Roman) era the legislative interest of the emperors intensified, and laws were now regulating the main aspects of public, private, economic and social life. For example, Constantine I was the first to regulate divorce and Theodosius I intervened in faith issues, imposing a specific version of the Creed. From Diocletian to Theodosius I, namely during approximately 100 years, more than 2,000 laws were issued. Justinian alone promulgated approximately 600 laws. Gradually, the legislative enthusiasm receded, but still some of the laws of later emperors, such as Leo VI's Novels, are of particular importance. The custom continued to play a limited role as a secondary source of law, but written legislation had a precedence.
There is no definitively established date for when the Byzantine period of Roman history begins. During the 4th, 5th, and 6th centuries the Empire was split and united administratively more than once. But it was during this period that Constantinople was first established and the East gained its own identity administratively; thus, it is often considered the early Byzantine period. Despite this, though, the legal developments during this period are typically considered part of Roman Law, as opposed to Byzantine Law, in part because legal documents during this period were still written in Latin. These developments, nevertheless, were key steps in the formation of Byzantine Law.
Soon after his accession in 527, Justinian appointed a commission to collect and codify existing Roman law. A second commission, headed by the jurist Tribonian, was appointed in 530 to select matter of permanent value from the works of the jurists, to edit it and to arrange it into 50 books. In 533 this commission produced the Digesta.
Although Law as practiced in Rome had grown up as a type of case law, this was not the "Roman Law" known to the Medieval, or modern world. Now Roman law claims to be based on abstract principles of justice that were made into actual rules of law by legislative authority of the emperor or the Roman people. These ideas were transmitted to the Middle Ages in the great codification of Roman law carried throughout by the emperor Justinian. The Corpus Iuris Civilis was issued in Latin in three parts: the Institutes, the Digest (Pandects), and the Code (Codex). It was the last major legal document written in Latin.
The world's most widespread legal system, civil law, is based on the Corpus (in, for instance, most of Europe, Asia, South America, and Africa, as well as in the mixed jurisdictions of South Africa, Scotland, Quebec, the Philippines and Louisiana).
Following Justinian's reign the Empire entered a period of rapid decline partially enabling the Arab conquests which would further weaken the Empire. Knowledge of Latin, which had been in decline since the fall of the West, virtually disappeared making many of the old legal codices almost inaccessible. These developments contributed to a dramatic weakening of legal standards in the Empire and a substantial drop in the standards of legal scholarship. Legal practice would become much more pragmatic and, as knowledge of Latin in the Empire waned, direct use of Justinian's "Corpus Juris Civilis" would be abandoned in favor of summaries, commentaries, and new compilations written in Greek.
The changes in the internal life of the empire which occurred in the years following the publication of Justinian's code called for a review of the legislation, so as to meet the requirements of the times. It was introduced within the framework of the reforms of Leo III the Isaurian (the first Isaurian emperor), and he also provided the modification of current laws. In 726 he issued the "Ecloga", that had his name as well as the name of his son Constantine. "Ecloga", referring to both the civil and criminal law constituted, as was declared in the title, a "rectification (of the Justinian legislation) towards a more philanthropic version". The membership of the editing committee is not known, but its primary mission was, on the one hand, to modify those dispositions not to be aligned with the current times and, on the other, to prevent judges from taking money for their actions and to help them to solve cases properly.
The dispositions of "Ecloga" were influenced by the Christian spirit, as well as by the common law, that protected and supported the institution of marriage and introduced the equality of all citizens in law. On the other hand, the penalties of amputation and blindness were introduced, reflecting the Byzantine concept in this period of changes. By means of his "Ecloga" Leo also addressed the judges, inviting them "neither the poor to despise nor the ones unjust to let uncontrolled". Besides, in his effort to deter bribery in the execution of their duties he made their payment local and payable by the imperial treasury. "Ecloga" constituted the basic handbook of justice dispensation up to the days of the Macedonian emperors, that also assumed legislative activity, whereas later it influenced the ecclesiastic law of the Russian Orthodox Church. Formerly the researchers attributed the juridical collections "Farmer's Law", "Rhodian Sea Law" and "Military Laws" to Leo III the Isaurian.
The structure of the act is original and it isn't taken from any other source, considering that Leon didn't want to complete layer legal reform. It seems that his goal was just to modify Justinian's legal tradition in the most important segments of legal life, while still adapting it to the needs and actions of the Middle Ages. It needed to be distinguished from its original model. Among the most important deviations from Justinian's Roman law are departure of consensuality when trading goods. So that a contract could exist, it was necessary for the object to either be given to the buyer or that a price be paid to the seller. As long as both sides finish their parts, the contract is not valid even if there is downpayment being given as validation element. Patria potestas is decreasing its power influenced by hellenistic and canon laws and the rights of women and children are increasing. But Ecloga brings even bigger and more controversial changes in criminal law, which can be seen in the frequent use of physical punishments, not typical for Justinian's law.
With the exception of a few cities, and especially Constantinople, where other types of urban economic activities were also developed, Byzantine society remained at its heart agricultural. An important source regarding law, which reflects in a particularly characteristic way the internal life of the Byzantine villages during the Middle Byzantine Era (7th - end of 12th century) is the Nomos Georgikos, also known as the Lex Rustica or Farmer's Law. Due to its importance, the Farmer's Law roused the interest of researchers from a very early stage. Ever since it has been one of the most discussed texts concerning the internal history of Byzantium. It has been suggested that, because of the major influences caused by the influx of Slavs into the Empire at the time the Farmer's Law was established, Slavic traditions were in fact an important influence of the Farmer's Law, both in terms of why it was developed and its content.
It is a private collection, continuously enriched, and refers to specific cases relevant to rural property within the framework of the Byzantine rural "community". As evident by the dispositions of the "Law", peasants were organized in "communities" and collectively responsible for the payment of the total tax the "community" was liable for, being obliged to pay as well the amounts corresponding to indebted members of the community. As for the chronology of its writing, since the text itself bears no specific date, it is placed somewhere in between the second half of the 6th century and the middle of the 14th. Very early on, it was acknowledged as a legal handbook of great importance and greatly influenced much of the law of the Slavic countries and especially Serbia, Bulgaria and Russia.
Dating problems, similar to the ones of the "Farmer's Law", presents a code of equal character, the "Rhodian Sea Law" (Nomos Rhodion Nautikos). Written probably between 600 and 800, it is a collection of maritime law regulations divided into three parts. The first part refers to the ratification of the "Naval Law" by the Roman emperors. The second specifies the participation of the crew in maritime profits and the regulations valid on the ship, while the third and largest refers to maritime law, as for example to the apportionment of responsibility in case of theft or damage to the cargo or the ship. The "Naval Law" was included in the Basilika of Leo VI the Wise as a complement to book 53.
In accordance with the model of the secular legal associations, the canons of the ecclesiastic councils concerned ecclesiastic issues and regulated the conduct of the clergy, as well as of the secular as concerned matters of belief. The "In Trullo" or "Fifth-Sixth Council", known for its canons, was convened in the years of Justinian II (691-692) and occupied itself exclusively with matters of discipline. The aim of the synod was to cover the gaps left in canon law by the previous Fifth (553) and Sixth Ecumenical Councils.
This collection of canons was divided into four parts:
a) The canons ratifying the doctrinal decisions of the first six ecumenical councils along with the teachings of the Fathers of the Church.
b) The canons specifying the obligations of the ministrational clergy.
c) The canons referring to the monks.
d) The canons referring to the secular. The influence of these canons carried on in the future and they were extensively annotated by Balsamon, Zonaras and Aristenos, the three great ecclesiastic jurists of the 12th century.
There were also other Ancient Church Orders no longer extant in Greek. Later, more-scientific collections emerged, including:
The following legal texts were prepared in the later Byzantine Empire:
Other jurists (including at least one Emperor) prepared private collections of cases and commentaries, but these did not form the body of law used by jurists at large. It is held that the 113 Novels of Leo the Wise fall into this category.
Lokin argues that while later legal texts tended to rearrange or explain the 6th century work of Justinian, rather than create new law, they did alter the locus of authority for law (legis vigor) from the Emperor to God. In Justinian's work, Mosaïc Law and God's authority support the Emperor, and are consultative, but do not temper his absolute authority. This process has already begun in the Ecloga, which states law is God-given by way of Isaiah 8:20, and is made explicit first in the Prochiron. There was, however, 'legislative creep' over this period, where the redaction of old laws and case law created new laws in effect, although not explicitly cited as such.
The best known center for legal teaching in the Byzantine Empire was the Law School of Constantinople. Founded in 425, it was closed in 717 as Constantinople was besieged by the Umayyads, reopening in 866 only. It then probably remained open until the Sack of Constantinople by the Crusaders in 1204.
During the early Middle Ages Roman/Byzantine Law played a major role throughout the Mediterranean region and much of Europe because of the economic and military importance of the Empire.
The Syro-Roman Law Book, a Syriac translation of a Greek original from the 5th century, was highly influential in eastern Christian communities after the early Muslim conquests. It was based on Roman case law and imperial statutes from the east of the empire.
After the Islamic conquests of the Eastern Mediterranean, the Islamic caliphates gradually codified their legal systems using Roman/Byzantine law as an important model. It has been suggested in fact that it was the Ecloga's publication that spurred the first major codification of Islamic imperial law.
Slavic legal traditions, including countries ranging from Bulgaria to Russia, were substantially influenced by the Farmer's Law. To a lesser extent the Ecloga and other Byzantine codices influenced these areas as well. During the 18th and 19th centuries, as Russia increased its contact with the West, Justinian's Code began to be studied thus bringing in this influence.
In Western Europe, following the fall of the Roman Empire, the influence of Roman/Byzantine law became more indirect though always significant during much of the Middle Ages. During the European Renaissance, Western scholars embraced Justinian's Code as a basis for jurisprudence, shunning many of the later legal developments of the Byzantine Empire such as the Ecloga. This was to a great extent affected by the East/West (Roman Catholic vs. Eastern Orthodox) split in the Church. The perception in the West was that Roman law that was recorded in Latin was truly Roman whereas later laws written in Greek was distinct and foreign.