Austrian legal history and the development of a national legal system is inextricably intertwined with the growth of Germanic law�at least up to the mid-18th century. Whatever primitive law existed in the region in the centuries before Christ was Celtic and Greek inspired at its most developed. In the 1st century B.C., when Roman conquerors organized the province of Pannonia, they brought with them the Pax romana and their own Roman law which was eventually applied to the entire population. Roman jurisprudence reached its zenith around the year 200, and even as it commenced its slow decline thereafter, its influence on Austrian legal development was lasting. As the empire sank into decay, classical Roman law was maintained in the ecclesiastical administration that succeeded in western Austria during the 6th and 7th centuries. The Bavarian expansion to the east effectively replaced the Lombardic tribal law that had evolved in Austria with more sophisticated evolutions of Frankish customary law. As Charlemagne�s power spread to the eastern lands, so did the innovative imperial legislation replace the inefficient and fragmented customs and collections that had been in use in the Danube Valley. The predominant Germanic codifications, tribal codes and collections�Visigothic and Burgundian�had existed side by side with the surviving Roman law for two centuries; the ones applied in the eastern Germanic areas were the Alamannic code of the early 7th century and the closely related Bavarian code of a hundred years later.
    The Frankish law imposed by the Carolingians applied throughout the empire and was the first Ius commune to succeed the long dormant Roman law. It was refined and developed into the feudal legal system that controlled central Europe throughout the Middle Ages, and in Austria, when combined with local custom, it maintained the social order into the early modern period. From the end of the Roman domination, the Church remained the single continuing force in Austria, and its contribution to legal development was the preservation of Roman legal principles within its own canonical evolution.
    The sources of Austrian law were many and varied: collections of local and regional customs and privileges, from Eike von Repgow�s Sachsenspiegel of about 1225 and the Augsburger Schwabenspiegel of 1275 that were carried into the region, to local versions such as the �sterreichische Landrecht of 1290 and the Landsordnung von Tirol of 1282 and the Steirm�rkische Landrecht of 1425. These collections were in use in x-large regions or many specific localities, but were supplemented by Stadtrechte of specific cities as well as by customs developed in feudal relations between noble and vassal. The B�uerliche Recht applied to the peasantry.
    The myriad of governing legal sources eventually gave way to the �received� Roman law�rediscovered and refined in northern Italy during the 12th and 13th centuries and accepted and applied as the new jus commune in Austria in the 15th century. Beginning in 1506, a wave of legislation swept through Austria aimed at unifying�at least on a regional basis�the dozens of legal compilations in use, with private law eventually being codified into Landrechtsordnungen and public law codified into Polizeiordnungen. From the reception of the Roman law in the 1400s, the thrust of Austrian legal development was towards the creation of a series of unifying codes. During the 16th and 17th centuries Austrian law, like that of the German states to the north, was subject to a series of privately inspired drafts and improvements on the regional and local codes aimed at improving the administration of justice. All through the 18th century, well before the French codification movement, the Austrian state set in motion the codification procedure, although against continuous opposition from nobles who feared imperial encroachment on their own powers and privileges.
    Criminal law was the object of the earliest successful codification. The Constitutio criminalis Theresiana was approved in 1769, at the same time that a civil code, the Codex Theresianus, was refused enactment. A general code of judicature followed in 1781, and a code of civil procedure in 1788. The criminal code was revised and enlarged in 1787; however, private law continued uncodified, except for a section dealing with family relationships (Josephinisches Gesetzbuch) which was enacted in 1787. Finally, as the end product of a codification process begun by Maria Theresa in 1760, the General Civil Code (Allgemeines B�rgerliches Gesetzbuch or ABGB) entered into force on 1 January 1812. This document, a much more detailed and extensive codification than the Code Napol�on, is the single controlling instrument in modern Austrian legal development. Like the French work, it is a collection of principles to be applied rather than precise provisions for every possible situation, as was the Prussian approach being employed in northern Europe at the same time. It is more heavily influenced by Roman law than the French, both codes being products of the natural law movement of the 18th century enlightenment. As much as possible, for its time the ABGB was a successful molding of the local Germanic-inspired jus commune of Roman law and the liberal approach of the natural lawyers.
    The ABGB had considerable influence on legal development elsewhere in the Empire during the years up to 1914, although ultimately this influence has proved transitory. Just as the First World War commenced, Austria further revised the ABGB with three Teilnovellen of 1914, 1915 and 1916 which somewhat remodeled the code along the lines of the newer German Civil Code (B�rgerliches Gesetzbuch or BGB) of 1900.
    The inter-war years were marked by serious economic dislocation and political strife; however, during this time the foundations of social and labor legislation laid by the Hapsburgs in the 1880s were enlarged upon and, in several radical spurts, a considerable body of modern social legislation was developed and enacted into law. This period, one of intermittently liberal constitutional advances, was surprisingly successful, considering the hazards and pitfalls such movements faced in the declining political and economic climate of the 1920s and 1930s.
    Austrian law underwent major changes as a result of the 1938 unification with Germany. The ABGB remained in force, although marriage law was altered; however, most importantly, commercial law underwent a total revision when the general commercial code in use since 1862 was abrogated and the German commercial code of 1897 was �received� by the Austrian state in 1938. In the post-war period private law, while retaining the structure developed under the Hapsburgs and the First Republic, has been changed to reflect the normal advances in corporate governances and business associations introduced in Europe in the last decades, even though the German commercial code has been retained. Criminal and public law has been greatly modernized and liberalized since 1970. Modern Austrian civil and commercial legislation generally takes its direction from German examples and thus, as well, frequently follows European Union models incidental to this tradition of close alliance with German lawmaking and legislative drafting.
    The present republic exists under the 1920 constitution that had been drafted by a group of scholars directed by the political scientist, Hans Kelsen. The basic document was revised in 1925 and again in 1929. Constitutional changes imposed by the Germans from 1938 to 1945 have been treated as if they never existed. Austrian constitutional law has evolved into a rather more pragmatic system; the basic document can�and has been frequently�amended by ordinary statutes resulting in ax-large , if not unmanageable, body of constitutional legislation.