Happy 1400th anniversary to Hild!

Today is Hild’s 1400th birthday. That is, Hild, who became St Hilda of Whitby, was born 1400 years ago, and November 17th is her feast day, so today seems like a good day for it. Happy Birthday Hild!

How do you say, fourteen hundreth in Latin? I will cheerfully admit that my Latin is rubbish, but I had a go anyway.

My first stab at it was quattourdecenennial, a word Hild would have found decidedly odd. I'm sure she would have been able to figure it out but it's a made-up word, English based on Latin—there's no evidence for anything like it in actual Latin (that I know of). Also, Latin counting would have used one thousand four hundred rather than fourteen hundred. The words we use for such things today, e.g. bicentennial, are formed from analogy to millenial, which is a late-Latin formation on the model of the Classical Latin words biennium and triennium. But according to Annie, a young Latinist I consulted (over beer in a pub), these mean a period lasting x years, and there's no Classical evidence for them having adjectival forms meaning on the second/third anniversary. Apparently, they're in a numerical class of their own. Annie suspects they might be based on the numeral adverbs, rather than the ordinal numbers—the bi- prefix is probably from bis, which means twice rather than two—and the closest you could get to 1400th on this model would be quaterdecienscentennial in English, quaterdecienscentennialis in Latin. 

At this point, the beer ran out. Well, okay, the pub still had beer but our capacity for it —at least as it relates to my making sense of Latin (minimal to begin with)—most definitely came to an end. So after a few days to recover, we switched the conversation to email. Which means that (much to my relief!) I can now quote directly:

If you instead take the late-Latin (in use c. 1250 CE in Britain) millenium or the English word centennial as the model, then quattourdecimcentennial(is) is probably more correct, using the cardinal number fourteen.You could even make an argument for quaternidenicentennial(is), using the distributive. All of these should make a certain amount of sense to an English speaker familiar with Latin. 

If you want something that a native speaker (or scholar of the language) might more readily write, millensimus quadringentensimus is probably close. Livy has mille et quadringentis for the cardinal 1400 (Ad Urbe Condita 26.50), and I'd assume mille(n)simus (et) quadringente(n)simus to be the ordinal equivalent (those 'n's are dropped pretty regularly, and the 'et' is entirely optional.) It would decline as a regular first/second declension adjective on the model of bonus, -a, -um; so 1400th year (nominative) would be millenimus quadringentesimus annus. It's a little trickier if you want to refer to a specific event which has recurred once every year for 1400 years, but you'd probably want to use anniversarius (yearly) in some form: eg, millesima quadringentesima anniversaria lupercalia, the 1400th annual Lupercalia. I really don't know enough about ecclesiastical Latin to say whether there were other conventions for writing numerals by the 7th century, but this would at least make sense when read. You are certainly correct that (written) Latin in Ireland was almost dialectally different—Hisperic Latin is a very strange creature, and I know nothing about that, either, except that the Altus Prosator is often given as the prime example.

And if you want to go deeper than that, feel free to consult Allen and Greenough’s New Latin Grammar and work it out yourself

For now, I declare that this is her fourteen hundredth anniversary: millesima quadringentesima anniversaria. Happy Birthday Hild! I shall raise a glass to you tonight.

Now I just have to figure out Happy Birthday in Old English. Ēadiġ ġebyrddæġ…?