When in the lesson Pope St Gregory...

He began going on about the regulus for a seccond I wasn't sure who he was speaking about but the centurion and the reguli filio made it clear and after a bit my mind worked and I realized regulus is a diminutive of rex i.e. a minor prince, a government grand or less grand poohbah.

Quid est quod regulus Dominum rogat ut ad ejus filium veniat, et tamen ire corporaliter recusat...?

The holy Doctor draws from this the admonition that we need to be watchful lest pride be our downfall:

Quid est hoc, nisi quod superbia nostra retunditur, qui in hominibus non naturam, qua ad imaginem Dei facti sunt, sed honores et divitias veneramur?

In any case, and omitting to waste much time lamenting the lack of Gregorys preaching to politicians in our countries of the West, I looked about in the dictionaries and noticed that regulus is also the name for a little bird, a wren, maybe. Which is a delightful thing. Some kind of snake or basilisk, not so delightful to me.  One can commit this to memory, if one likes: ‘regulus est serpens, avis, et rex parvulus omnis’.