Love-at-Arms by Rafael Sabatini

It was a week after the meeting 'twixt the niece of Guidobaldo and the Count of Aquila, when the latter--his wound being wellnigh healed--rode one morning under the great archway that was the main entrance to the city of Babbiano. The Captain of the Gate saluted him respectfully as he rode by, and permitted himself to marvel at the pallor of his Excellency's face. And yet, the cause was not very far to seek. It stood upon four spears, among a noisy flock of circling crows, above that very Gate---called of San Bacolo--and consisted of four detruncated human heads.

The sight of those dead faces grinning horribly, their long, matted hair fluttering like rags in the April breeze, had arrested Francesco's attention as he drew nigh. But when presently he came nearer and looked with more intentness, a shudder of recognition ran through him, and a great horror filled his soul and paled his cheek. The first of those heads was that of the valiant and well-named Ferrabraccio; the next that of Amerino Amerini; and the other two, those of his captured companions on that night at Sant' Angelo.