The Proculeian or Pegasian school was one of the two most important schools of law in ancient Rome during the 1st and 2nd centuries AD.
The Proculeians originally took their name from the prominent jurist Proculus, but later came to often be called "Pegasians" after the prominent Proculeian Plotius Pegasus. However the tradition on which the school was based comes from the jurist Marcus Antistius Labeo. Labeo spent half the year convening sessions at actual schools with regular students who then carried forth his views and perspectives on the law.
They were often contrasted with the Sabinian school, a rival school operating in roughly the same time and place, and were (very generally) considered the more progressive of the two, while the Sabinians were seen as more advocates of legal conservatism. Proculeians were thought to "push a legal principle to all its logical consequences," and the legal tradition they inherited from Labeo was one of liberalism influenced by a keen understanding of the science of the day. The Proculeians tried to enlarge the scope of Roman law, and tried to push legal innovations into practice such as were suggested by their liberal philosophy and the principles of reason.
The progressive and conservative natures of the schools increased over time, and there came to be wider chasms between the two, which is perhaps why the schools were named after later prominent disciples and students, and not after their originators (the Proculeian school being named after Proculus but originated by Labeo, and the Sabinian school being named after Masurius Sabinus but originated by Gaius Ateius Capito).
The Roman legal compendium known as Digest records many decisions in which the Proculeians advocated. Among these were: