Page "Aloysius Lilius" Paragraph 4

The processes of consultation and deliberation meant that the reform to the calendar did not occur until 1582, six years after the death of Luigi Lilio in 1576.

The reform had by then received some modifications in points of detail by the reform commission, in which one of the leading members was Clavius, who afterwards wrote defences and an explanation of the reformed calendar, including an emphatic acknowledgement of Lilio's work, especially for his provision of a useful reform for the lunar cycle: " We owe much gratitude and praise to Luigi Giglio who contrived such an ingenious Cycle of Epacts which, inserted in the calendar, always shows the new moon and so can be easily adapted to any length of the year, if only at the right moments the due adjustment is applied.

" The papal bull ( Inter gravissimas ) was issued on 24 February 1582, ordering Catholic clergy to adopt the new calendar, and exhorting Catholic sovereigns to do the same.