The verb mori ("to die") has the unusual past participle mortuus ("dead"). The stem of the participle is mortu-, the only example of a past participle stem ending in a vowel I can think of. (If my memory fails, please let me know!) I would instead expect mortus or perhaps moritus.

The future participle is moriturus. This would give a little discrepancy between mortus (from which one might expect morturus) and the future participle, but this is not unique. While usually the future participle comes directly from the past one by adding -ur-, there are examples of similar behaviour, like ortus and oriturus. See this question for discrepancies between past and future participles.

I never understood why mortuus has two Us instead of being simply mortus. Can anyone explain how this form came about? Was this participle always like this before the classical times? Are there other similar past participles in Latin?

There is a separate question about the pronunciation of mortuus, and all evidence points towards it being trisyllabic. Both Us are therefore vowels.


1 Answer 1


This is an interesting relic of the PIE conjugation system.

In Proto-Indo-European, there were quite a lot of different "participles" (or derived adjectives, it's not clear how much they were considered "the same as" the source verbs). One of these was -tós, which became the perfect passive participle -tus in Latin and the adjectivizer -tós in Greek (as well as, eventually, -ed in English).

But there was another one, which changed significantly in Latin: -wós, the perfect active participle. In Latin, this was the source of -v- in the perfect stems. But in a few specific verbs, the perfect active participle survived on its own as an adjective. Mortuus is one of those. Vīvus is another. (The suffix -wós itself survived as -uus/-vus, so a Roman might analyze mortuus as mort- + -uus.)

The verb that would become morior also had its own -tós participle, which would have been something like *mortus by the time it reached Latin. (We know this from cognates like Sanskrit mṛtá "dead".) But the -wós adjective that would become mortuus was far more popular and ended up displacing it. Vīvus, whose corresponding verb (ironically) died out completely, just continued to be an adjective.

  • Interesting! It seems plausible that the active perfect participle together with esse lead to much of Latin perfect stem conjugation, which would answer the question on perfect and esse. Is that the way the -w- of -wós became the -v- in Latin perfect stems?
    – Joonas Ilmavirta
    Commented May 13, 2018 at 19:53
  • 1
    @JoonasIlmavirta and Draconis, If answer was as simple as what is written here now, Latin would probably have *morvus. Page for root *mer- mentions reconstructed 3 adjectives meaning "dead": *mr̥-tós, *mr̥-t-wós, *mr̥-wós (the last one preserved in Proto-Celtic). Michiel de Vaan (2008)'s dictionary in entry for morior (page 390) says: 「The formation of *mrtu̯o- ‘dead’ for PIE *mr̥to- (as in Slavic) may be due to a contamination with *mr̥u̯o- as attested in Celtic.」 (Proto-Slavic had *mьrtvъ.)
    – Arfrever
    Commented Aug 24, 2023 at 20:49
  • And I think that vīvō, vīvere can be considered to be the corresponding verb for adjective vīvus.
    – Arfrever
    Commented Aug 24, 2023 at 21:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.