What was the ultimate end of Bar Kochba (Ben Koziva), who was believed by Rabbi Akiva to be Moshiach?

In Hilchos Taaniyos, Maimonides writes that Ben Koziva was killed by the Romans. Raavad, by contrast, writes that he was killed by order of the Rabbinical court: “The Sages dispatched people to test whether or not he could judge by his sense of smell, and since he could not, they killed him.”

It could be argued that there is no difference of opinion as to what actually happened, and that all agree that he was killed by the gentiles. The difference of opinion may be understood as follows:

According to the view of Maimonides (following the view of R. Akiva), that Mashiach does not have to be able to work miracles and wonders, Ben Koziva was killed simply “because of [his] sins,” and not because he was unable to “judge by his sense of smell.”

According to the view of Raavad (following the view of the Talmud in Sanhedrin and the opinion of R. Yochanan ben Torta, that Mashiach does have to be able to work miracles and wonders, Ben Koziva was liable to the death penalty because he was incapable of “judging by his sense of smell.”

The rationale is as follows: The absence of this sign proved that he was not Mashiach; he battled against the gentiles (thinking that he was Mashiach despite his inability to judge by his sense of smell, because he held the view of R. Akiva); many Jews perished in these battles; accordingly, he was now liable to the death penalty since he had caused Jewish blood to be spilled in vain. Even though in fact it was the gentiles who killed him, they “killed a man who was already [sentenced by the beis din to be] killed.” Thus, too, Ridbaz quotes the Talmud (“Seeing that he was unable to judge by his sense of smell they killed him”) and explains: “This means that they dissociated themselves from him and the gentiles came and killed him.”

(Sources: Hilchot Taaniyot 5:2; Raavad’s Gloss on Hilchot Melachim 11:3; Sanhedrin 93b; Likutei Sichot vol. 27, p. 200.  Excerpted from From Exile to Redemption, published by Sichot in English, p. 172)