The feature is named after the Roman writer and philosopher Ambrosius Macrobius (4th-5th century) who placed on the world map the southern polar land envisaged by Aristotle.
All later writers, including Macrobius about 430, Bede in 725, and other medieval computists (calculators of Easter), continued to state that the bissextum (bissextile day) occurred before the last five days of February.
The work takes material from the Attic Nights by Aulus Gellius, the Banquet of the Sophists by Ateneo, the Saturnalia of Macrobius, the Memorable deeds and sayings of Valerius Maximus, the Inventor of all things by Polidoro Virgilio, the Moralia and Parallel Lives of Plutarch and, above all, the Natural History of Pliny the Elder.
Among the extant fragments there is mention of Io, Cadmus and the Argonauts, but the most significant fragment is the testimony of Macrobius that states that Peisander's history of the world began from the marriage of Zeus and Hera.