At least one manuscript has "our Lord" rather than "their Lord." Thus, the KJV:
And their dead bodies shall lie in the street of the great city, which spiritually is called Sodom and Egypt, where also our Lord was crucified.
My 27th edition of Nestle-Aland prefers "their."
Either way, it is a very difficult passage for historicists; my
New Jerome Biblical Commentary (Catholic, 1990s, historical-critical) simply refuses to comment on the image at all.
It is beyond dispute that here you have the image of
ho kyrios being crucified, and the image itself is presented not only in opposition to the otherwise clear tradition that Jesus of Nazareth was crucified in the city of Jerusalem, but also in an explicitly "spiritual," mythical, apocalyptic discourse. There is no way to read this text as an instance of Christian tradition spiritualizing an originally historical crucifixion. The link to any type of Markan passion narrative is utterly absent, while the image of the Lord being crucified in one of the lower, wicked realms, exactly where the beast rises up from the abyss, is unmistakeable. A lot of historicists have mocked Earl Doherty's claim that there was a dominical crucifixion in a spiritual realm, but this is exaclty what the text of Revelation says.
Rev 11:9-12 continues the story of the mysterious two witnesses, who lie dead in the street
for three and a half days before they are resurrected by the spirit of life from God, and called to ascend to the heavenly realm. All mythical, death and resurrection motifs, including the famous "three days."