The 1960 Code of Rubrics replaced the "Rubricae Generales Missalis", which had been in the Tridentine Roman Missal since its first edition in 1570 and had been amplified and revised by Pope Clement VIII in 1604. This had been supplemented, since the 1920 edition, by the "Additiones et Variationes in Rubricis Missalis ad normam Bullae "Divino afflatu" et subsequentium S.R.C. decretorum" (Additions and Variations to the Rubrics of the Missal in accordance with the Bull "Divino afflatu" and subsequent decrees of the Sacred Congregation of Rites), which indicated the changes in the Roman Missal that followed from the reform of the Roman Breviary by Pope Pius X.