Pope Gregory XIII
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Pope Gregory XIII was head of the Catholic Church and ruler of the Papal States from 13 May 1572 to his death in April 1585. He is best known for commissioning and being the namesake for the Gregorian
Portrait by Bartolomeo Passarotti (c. 1586, Friedenstein Palace, Gotha)
Portrait of Gregory XIII by Lavinia Fontana (oil on canvas, private collection)
Detail of the tomb of Pope Gregory XIII celebrating the introduction of the Gregorian calendar.
Ugonottorum Strages medal
Julian calendar
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The Julian calendar is a solar calendar of 365 days in every year with an additional leap day every fourth year. The Julian calendar is still used as a religious calendar in parts of the Eastern Ortho
Pope Gregory XIII
…Aloysius Lilius and aided by Jesuit priest/astronomer Christopher Clavius, who made the final modifications. This calendar is more accurate than the Julian calendar, which treats each year as 365 days and 6 hours in length, even though the actual length of a year is slightly less (365 days, 5 hours, and 49 minutes…
The Tusculum portrait of Julius Caesar
Russian icon of the Theophany (the baptism of Jesus by John the Baptist) (6 January), the highest-ranked feast which occurs on the fixed cycle of the Eastern Orthodox liturgical calendar
Marine sandglass MMM