Sixtus was a Roman name. It is the Latin form of a Greek name, ξυστός, ('polished). It was originally Latinized Xystus, which is the earliest form recorded for the first three popes now known as Sixtus. In all, there have been five of these so far, and they are the most notable bearers of the name, which is not common (although in 2017 the politician Jacob Rees-Mogg named his sixth child . Sixtus Dominic Boniface Christopher). Sixtus should not be confused with the common Roman name Sextus ('sixth' - though not necessarily denoting a sixth child); but this confusion has long been possible (and still may be, in the Rees-Mogg family). (Kelly & Walsh 2010 say "[Irenaeus] lists twelve bishops of Rome between Peter and Eleutherius" - bishop in Irenaeus' own day and known to him. This list explicitly links the twelve bishops to the twelve apostles: Sixtus is, rather suspiciously, the sixth" - suggesting that there was a confusion in the second century.
- The adjective sistine means 'to do with Sixtus', or 'done by Sixtus'. It is famously applied to the chapel in the Vatican used for the conclave of Cardinals meeting to elect a new Pope, and gloriously decorated by Michelangelo with a wall of the Last Judgement and a ceiling of the creation of Adam, as well as by Botticelli, Bernini and many others. The Sistine Chapel is so called because it was carried out at the behest of Pope Sixtus IV: before him, it was known as the Cappella Magna ('great chapel). Sixtus rebuilt it between 1477 and 1480.
- The Sistine Vulgate was a revision of the Vulgate translation of the Bible (originally by St Jerome, c.347-420) commissioned by Pope Sixtus V between 1563 and 1590.
- The Sistine Madonna, on the other hand - a painted altarpiece by Raphael (1483-1520) - was painted for the Benedictine monks of the Monastery of San Sisto (= Saint Sixtus) in Piacenza. They wanted the image to contain both Saint Sixtus - the Canonized Pope Sixtus II, who was martyred in 258, and Saint Barbara.