Speaking of that chapter of history, the old man sighed with bitter regret.
Tips
history
From the Jin-dynasty historian Wang Yin's 《晋书·刘锟传》: 臣所以泣血宵吟扼腕长叹者也 - this is why your servant weeps blood, chants through the night, and wrings his wrist with long sighs. 扼腕 (to grip one's own wrist) is a classical gesture of helpless indignation.
register
Literary register. Fits reports, eulogies, and sports commentary about missed opportunities or tragic outcomes - stronger and more formal than 可惜 or 遗憾.