Who did Benjamin think Thon Thaddeo was?

Question

In Miller's A Canticle for Leibowitz, at the end of the Fiat Lux section, Benjamin, the seemingly immortal Jewish hermit, interrupts Thon Thaddeo's farewell dinner.

As I recall, he (Benjamin) gets very excited, grabs Thon Thaddeo's arm, and looks searchingly at him. However, this quickly turns to disappointment, and he turns to the assembled monks and says something to the effect of "It's not him" or "he is not the one".

He came close to the lectern, paused. His eyes twitched over the startled speaker. His mouth quivered. He smiled. He reached out one trembling hand toward the scholar. The thon drew back with a snort of revulsion.

The hermit was agile. He vaulted to the dais, dodged the lectern, and seized the scholar's arm.

"What madness-"

Benjamin kneaded the arm while he stared hopefully into the scholar's eyes.

His face clouded. The glow died. He dropped the arm. A great keening sigh came from the dry old lungs as hope vanished. The eternally knowing smirk of the Old Jew of the Mountain returned to his face. He turned to the community, spread his hands, shrugged eloquently.

"It's still not Him," he told them sourly, then hobbled away.

Who was he looking for, and why did he think Thon Thaddeo may have been him? Why did he decide Thon Thaddeo wasn't, after all?

Answer 1

One of the explanations for Bejamin's character is that he is the Wandering Jew, and is forced to live until the Second Coming.

So, if he is the Wandering Jew, then he's most likely under the impression that Thon Thaddeo is the Second Coming, and after so long on Earth (Per Wikipedia,'Fiat Lux' takes place in 3174) he might just be checking anyone held in high regard. It's also been a long while since I read it, and don't have the book with me to review that scene, but since it happened at Thon's farewell dinner, Benjamin might have gotten some serous Last Supper vibes off the scene and that could have contributed.

As for why he decided Thon wasn't 'The One'? Well, if Thon really WAS Christ, Benjamin's punishment would be over and he'd be wandering the Earth no longer. He's still around to wander the Earth, so Thon must not have been Christ.

Answer 2

If I remember correctly, Benjamin, the Wandering Jew was actually Lazarus, whom Jesus raised from the dead. Whether Lazarus or not, I recall the book implied that he had met Jesus face to face, so would be able to recognise that Thon was not the same person.