Two Messiahs
The idea that there will be more than one Mashiach does not come up that often in Jewish writings. We are referring to the Mashiach Ben Yosef, and the Mashiach Ben David. Most are familiar with the Davidic Messiah, and many are not aware that there is a second Messiah descended from Yosef.
Rav Kook spoke about this quite openly as he saw the coming redemption of the Jewish people. The role of the Mashiach Ben Yosef would be very much like Yosef himself. He would lay the physical groundwork for the people so that they would be prepared for the coming of the Mashiach Ben David.
The problem we have is that we are not given a clear description of who this Yosef Messiah will be. We are told in Masechet Succah that he will die, and will have a massive funeral. There will be great mourning for the loss of this great leader.
Strangely, the Mashiach Ben Yosef is brought up incidentally. The Talmud was explaining they created a separate gallery for the women in the Second Temple. The reasoning for the necessity of such a gallery is as follows: If at the funeral of Mashiach Ben Yosef where there was no levity, but only sadness, they, nevertheless, separated the men and the women, how much more so must there be a separation on Succot, when there is great levity.
Many have speculated who this person is. Some have even suggested Theodore Herzl! Others felt that it was more of a concept rather than a real person.
I do not recall this idea of Mashiach Ben Yosef brought up in the Yeshiva fifty years ago. The fact that it is coming up more and more often is a true sign that the Redemption is near. We are living in truly amazing times!