Sometimes words with Hs in them were spelled with CH in medieval Latin, e.g., MICHI for MIHI or NICHIL for NIHIL. My own WDI is that the orthography was to explicitly indicate a pronounced H rather than a silent one.

The {h} in Classical Latin was probably not pronounced (e.g., (h)arena 'sand'). Medieval Europe is another thing. I always assumed the spelling michi / nichil were pronounced with voiced palatal or velar fricatives, rather than stops.

So, armigers bear heraldic arms and heralds bear messages. And who arms the bears? Arma ursorum cano.