The Theodosian Code is a compilation of the Roman legislation from the times of the Emperor Constantine to the times of Theodosius II. The work was begun in 427 and finished in autumn 437 when it was accepted for publication. It was promulgated in February 438 and came into effect from the beginning of the year 439.

 

The compilation consist of sixteen books in which all imperial constitutions are gathered beginning with the year 312. Books 1-5 did not survive and are reconstructed from the manuscripts of the Lex Romana Visigothorum, i.e. the Breviary of Alaric, the legal corpus published in 506 by the Visigothic king, Alaric, containing excerpts from the Theodosian Code equipped with explanatory notes (interpretationes), post-Theodosian novels and several other juristic texts.

 

A new compilation was undertaken during the reign of the emperor Justinian. A committee of ten persons prepared and promulgated the Codex in 529. It was quickly outdated because of the legislative activities of the emperor and therefore its revised version had to be published in 534. The Codex together with the novels, the Pandecta, a digest of juristic writings, and the Institutes, an introductory handbook are known under the medieval name "Corpus Iuris Civilis".