One of the many excellent things about being a Latin teacher is the time I get to devote myself to questions of absolutely no importance or relevance to the wider world. These include such things as 'Why is this noun ablative?', 'Why is this verb subjunctive?' and 'What on earth is Lucretius talking about?'.
The other day I was pondering my old school motto: Detur Gloria Soli Deo- 'Let Glory be given to God alone.' It's an interesting motto from a grammatical point of view- Detur is a iussive subjunctive ('let...'), and it's passive as well ('...be given'), and soli...
Hang on a second, surely solus, -a, -um is a 1st/2nd declension adjective? Surely if it were to agree with deo, the ending should be solo? Could it be there was a grammar mistake in my old school motto? Or did it perhaps mean something else? Perhaps soli was not from solus, -a, -um (alone) after all, but perhaps from sol, -is (the sun) and in apposition to deo- in which case the motto would mean something like 'let glory be given to the sun as god'. Or perhaps it was from solum, -i (the ground, earth, soil), and was not dative, but genitive, meaning 'let glory be given to the god of the soil.'
As all this and more raced through my mind, I reached for my trusty Lewis and Short, and read the following:
solus, -a, -um, gen. solius; dat. soli
So soli is an irregular form, but does in fact mean what I thought it did. I could sleep easy once more, with the words of Socrates ringing in my ears: 'The unexamined motto is not worth having.'