''Supremi disciplinae'' was a ''

motu proprio In law, ''motu proprio'' (Latin for "on his own impulse") describes an official act taken without a formal request from another party. Some jurisdictions use the term ''sua sponte'' for the same concept. In Catholic canon law, it refers to a do ...

'' released on 2 July 1911 by

Pope Pius X Pope Pius X ( it, Pio X; born Giuseppe Melchiorre Sarto; 2 June 1835 – 20 August 1914) was head of the Catholic Church from 4 August 1903 to his death in August 1914. Pius X is known for vigorously opposing modernist interpretations of ...

that reduced the number of holy days of obligation within the Roman Catholic Church. It reduced the number of such non-Sunday holy days from 36 to 8. The present list was established in 1917.''Codex Iuris Canonici'' canon 1247 (1917).

References

Motu proprio {{RC-Canon-law-stub