The man who rode on Madonna's right turned in his saddle and put up his hand as if to beckon Stefano.

I was regaling him with one of the choicest of Messer Sacchetti's paradoxes, gurgling, myself, at the humour of the thing I told.

I paid no heed to the sign.

I continued to expound my quip, as though we had the night before us in which to make its elusive humour clear.

But out of the tail of my eye I watched my good friend Stefano, and I saw his right hand steal round to the region of his back where I knew his dagger to be slung.