Christians generally believe that the Messianic prophecies of the OT have already come to pass. My question is, to qualify as a Christian does that Messiah necessarily have to have been Jesus of Nazareth, or would anyone (e.g. Judas Iscariot) do?
This may be more appropriate in Gread Debates.
Well, seeing how Christians are so named for their belief in Jesus of Nazareth, surnamed the Christ (yes, I know what it means), I would say you have to believe in him to be one.
Otherwise, to use your Judas example, you’d be a Iscariotian. Or a Jonesian. Or whatever.
Technically speaking, one might be called a Chrisitian if one followed anyone dubbed the Christ. Practically speaking, A) I have never heard of anyone other than Jesus considered the Christ, and B) even if there were such another, “Christian” as it is used and has been used for centuries means a follower of said Jesus - if someone else gets dubbed “Christ” there would need to be another term to avoid confusion.
Well, since “Christ” (Christos) just means “messiah” in Greek, if Judas was the messiah, then we’d call him Judas Christ*, and a “Christian” would worship Judas. That could get kinda confusing if there were a bunch of Messiahs running around. Since the worhipers of Jesus laid claim to the term “Christian” first, I think it only polite to let them keep it. 
*assuming his sacred texts were in Greek, and we preserved the Greek word “Christ” as we do fo Jesus.
Actually, it means “annointed one”. And since a whole lot of people have been annointed over the years, there are a lot of people who could have been called “the Christ.”
Not all Christians, especially in the first 2 centuries, have/do believe in Jesus being a messiah, son of God or any other special designation. Basically a Christian is someone who uses that term to describe themselves.
Note that all-too-often you will read something that starts:
“As a Christian I believe …”
and what follows may be a majority opinion, but there is certainly a group of Christians who don’t believe the same thing.
Judas isn’t the Messiah: he’s a very naughty boy.
Ah, but you miss the important point. “Messiah” itself is literally translated as “the annointed one”, so *Christos *does, in fact, mean Messiah.
Moved from GQ
samclem
A lot of people have been called “Messiah” over the years, most recently, Rebbe Menachem Mendel Schneerson, who died in 1994 and hasn’t returned. AFAIK, only the followers of one such claimant call themselves “Christians.”
You appear to be confusing the interrelationships between separate words, their definitions, and their etymologies.
It is true that different Jewish groups have, over the last couple of thousand years, perceived different individuals as the Messiah.
It is true that Messiah (or its actual Hebrew original) means “Anointed” and that the Greek Christos was a direct translation of that word.
However, with the growth of the followers of Jesus of Nazareth and their propagation of the word “Christ” to mean Jesus (and their self-identification with the word “Christian”), the separate word “Christian” and with some small variations, the use of the Greek-derived “Christ” have come to be associated explicitly with that body of belief.
While there is no rule that prohibits applying the word “Christ” to some other person or applying the word “Christian” to the followers of that person, in reality it would be a futile and confusing effort to do that. Nearly 2,000 years of tradition in every European language and nearly 500 years of tradition in the rest of the languages of the world have removed the words “Christ” and “Christian” from their etymological roots and confirmed upon them the meanings of “appellation of Jesus of Nazareth” and “followers of Jesus of Nazareth.”
So you could, if you chose, recognize any number of persons as the anointed of God, call them “Christ” and call yourself “Christian” in the sense of “follower of this other person,” but you would never be understood by 99.999% of the world and your usage would simply be confusing.