I like the way Walpole has drawn out a picture of this crowd (most of them domestics), and their reactions.

They are an amusing bunch.

They are introduced shouting;
The prince! The prince! The helmet! The helmet!

and they are '...thunderstruck themselves at the miracle of the helmet.

The crowd couldn't answer Manfred's enquiries.
However, as it seemed to be the sole object of his curiosity, it soon became to the rest of the spectators, whose conjectures were as absurd and improbable as the catastrophe itself.

And then;
Some of the vulgars had run to the great church....and came back open mouthed.
Interesting use of the word 'vulgar'. I think then it meant 'not cultivated'.

The silliest part the crowd plays is when Manfred accuses the peasant of sorcery;
The mob, who wanted some object within the scope of their capacities on whom they might dischatge their bewildered reasonings, caught the word from the mouth of their lord, and re-echoed, Ayay, 'tis he, 'tis he...'

And lastly, Manfred orders the peasant to be kept prisoner under the helmet;
The generality were charmed with their Lord's decision......his commands even cheerfully obeyed.

I enjoyed reading the behaviour of the mob.
The novel has started with some humour, I wonder how much of it will continue.