Sacrae Disciplinae Leges is the title of an apostolic constitution

Apostolic constitution

An apostolic constitution is the highest level of decree issued by the Pope. The use of the term constitution comes from Latin constitutio, which referred to any important law issued by the Roman emperor, and is retained in church documents because of the inheritance that the canon law of the...

by Blessed John Paul II, issued on January 25, 1983.

This apostolic constitution instituted the 1983 Code of Canon Law for the Latin Rite Church. In contrast, the Code of Canon Law for the other 22 Eastern Churches dates to the Ap. Const. Sacri Canones of 18 October(October 18, 1990)1990.