religion thomas tallis
The Julian calendar , proposed by Julius Caesar in 46 BC ( 708 AUC ), was a reform of the Roman calendar . It took effect on 1 January 45 BC ( AUC 709 ) ( shortly before the Roman conquest of Egypt ), by edict . It was the predominant calendar in the Roman world , most of Europe , and in European settlements in the Americas and elsewhere , until it was refined and gradually replaced by the Gregorian calendar , promulgated in 1582 by Pope Gregory XIII . The Julian calendar gains against the mean tropical year at the rate of one day in 128 years . For the Gregorian the figure is one day in 3 , 030 years . The difference in the average length of the year between Julian ( 365 . 25 days ) and Gregorian ( 365 . 2425 days ) is 0 . 002 %. Thomas Tallis ( c . 1505 -- 23 November 1585 by the Julian calendar still then in use in England ) was an English composer who occupies a primary place in anthologies of English choral music , and is considered one of England ' s greatest composers . He is honoured for his original voice in English musicianship . No contemporary portrait of Tallis survives : that painted by Gerard Vandergucht ( illustration ) , dates from 150 years after Tallis died , and there is no reason to suppose that it is a likeness . In a rare existing copy of his black letter signature , the composer spelled his last name `` Tallys . '' Pope Gregory XIII ( 7 January 1502  10 April 1585 ), born Ugo Boncompagni , was Pope of the ___MASK9___ from 13 May 1572 to his death in 1585 . He is best known for commissioning and being the namesake for the Gregorian calendar , which remains the internationally accepted civil calendar to this day .