Thirty Days Hath September
"Thirty Days Hath September..." or "Thirty Days Has September..." is a traditional verse mnemonic used to remember the number of days in the months of the Julian and Gregorian calendars. It arose as an oral tradition and exists in many variants. It is currently earliest attested in English, but was and remains common throughout Europe as well.
The irregularity of the lengths of the months descends from the Roman calendar, which came to be adopted throughout Europe and then worldwide. The months of Rome's original lunar calendar would have varied between 29 and 30 days, depending on observations of the phases of the moon. Reforms credited to Romulus and Numa established a set year of twelve fixed months. Possibly under the influence of the Pythagoreans in southern Italy, Rome considered odd numbers more lucky and set the lengths of the new months to 29 and 31 days, apart from the last month February and the intercalary month Mercedonius. Its imperfect system and political manipulation of intercalation caused it to slip greatly out of alignment with the solar year, which was known to consist of ¼ of 1461 days (rather than 1460 days) by the time of Meton in the 5th century BC. Rather than adopt a new system like the Egyptian calendar, which had 12 months of 30 days each and a set, annual intercalary month of 5 days, Caesar aimed for his 46 BC reform to maintain as much continuity as possible with the old calendar. Ultimately, Mercedonius was removed, the four existing 31-day months were maintained, February was left unchanged apart from leap years, and the needful additional ten days of the year were added to the 29-day months to make them either 30 or 31 days long.
By the Renaissance, the irregularity of the resulting system had inspired Latin verses to remember the order of long and short months. The first known published form appeared in a 1488 edition of the Latin verses of Anianus:
In 2011, the Welsh author Roger Bryan discovered an older English form of the poem written at the bottom of a page of saints' days for February within a Latin manuscript in the British Library's Harleian manuscripts. He dated the entry to 1425 ±20 years.
"September" and "November" have identical rhythm and rhyme and are thus poetically interchangeable. The early versions tended to favour June and as late as 1891 it was being given as the more common form of the rhyme in some parts of the United States. It is less common now and September variants have a long history as well. A manuscript copy of the verse from c. 1555 runs:
Variants appear throughout Europe. The typical Italian form is
The various forms of the poem are usually considered a doggerel nursery rhyme. In the c. 1601 academic drama Return from Parnassus, Sir Raderic's overenthusiastic appreciation of its poetry is of a piece with his own low level of culture and education.
It has, however, also earned praise. It's been called "one of the most popular and oft-repeated verses in the English language" and "probably the only sixteenth-century poem most ordinary citizens know by heart". Groucho Marx claimed "My favorite poem is the one that starts 'Thirty Days Hath September...', because it actually means something." On the other hand, the unhelpfulness of such an involved mnemonic has been mocked, as in the early 20th-century parody "Thirty days hath September / But all the rest I can't remember" It continues to be taught in schools as children learn the calendar, although others employ the knuckle mnemonic instead.
"Thirty Days Hath September..." is also occasionally parodied or referenced in wider culture, such as the 1960 Burma-Shave jingle "Thirty days / Hath September / April / November and June the / Speed offender".
- "How Old is 'Thirty Days Has September...'", Blog, Dictionary.com, 18 January 2012.
- Mommsen (1894), Vol. I, Ch. xiv.
- Mommsen (1894), Vol. V, Ch. xi.
- Rüpke (2011), p. 112.
- Rüpke (2011), p. 113.
- Ballew, Pat (1 September 2015), "On This Day in Math", Pat's Blog.
- Anianus, Computus Metricus Manualis, Strasbourg. (in Latin)
- Misstear, Rachael (16 January 2012), "Welsh Author Digs Deep to Find Medieval Origins of Thirty Days Hath Verse", Wales Online, Media Wales.
- Bryan (2011).
- Bryan, Roger (30 October 2011), "The Oldest Rhyme in the Book", The Times, London: Times Newspapers.
- "Memorable Mnemonics", Today, London: BBC Radio 4, 30 November 2011.
- Cryer (2010), "Thirty Days Has September".
- Grafton (1562).
- Holland (1992), p. 64–5.
- Ganvoort, A.J. (August 1891), "Value of Music in Public Education", The Ohio Educational Monthly and the National Teacher, Vol. XL, No. 8, p. 392.
- Stevins MS.
- OCDQ (2006), p. 45.
- Onofri, Francesca Romana; et al. (2012), Italian for Dummies, Berlitz, pp. 101–2.
- Anon. (1606), Act III, sc. i.
- Smeaton (1905), p. xxvi.
- The Cincinnati Enquirer, Cincinnati, 20 September 1924, p. 6.
- "Thirty Days", Jingles, Burma-Shave.org, 2005.
- Anon. (1905), Smeaton, Oliphant, ed., The Return from Parnassus, London: J.M. Dent & Co., a reprint of the 1606 The Returne from Pernassus, or, The Scourge of Simony.
- Bryan, Roger (2011), It'll Come In Useful One Day, Llanina Books.
- Cryer, Max (2010), Common Phrases... and the Amazing Stories Behind Them, New York: Skyhorse Publishing.
- Grafton, Richard (1562), Abridgement of the Chronicles of Englande, London: Richard Tottell.
- Holland, Norman N. (1992), The Critical I, New York: Columbia University Press.
- Ratcliffe, Susan, ed. (2006), Oxford Concise Dictionary of Quotations, 5th ed., Oxford University Press.
- Rüpke, Jörg (2011), Richardson, David M.B., ed., The Roman Calendar from Numa to Constantine: Time, History, and the Fasti, Malden: Wiley-Blackwell, a translation of the 1995 Kalendar und Öffentlichkeit.
- Mommsen, Theodor (1894), Dickson, William Purdie, ed., The History of Rome, a translation of the 1861 &c. Romische Geschichte.
- Ochampaugh, Raenell Dawn Cardile; et al. (1997), "Days of the Month Poem", Leap Year Day, Honor Society of Leap Year Day Babies: 91 English variants of the poem