The Edomites were descended from Esau who was renamed Edom. Esau was Jacobs brother and Jacob was later renamed Israel. He was the father of 12 sons who became the Israelites, or 12 tribes of Israel.
However Esau (to the dismay of his parents) intermarried with the Canaanite tribes (whom the Israelites were forbidden from intermarrying with). Ever since this point his new descendants - the Edomites or Idumeans - became enemies of Israel.
It's quite strange, since Jacob intermarried with Rachel and Leah, who were daughters of Laban, who was a Syrian. Surely the Syrians who were not Israelites would have also been forbidden for inter-marriage with Istraelites. They also followed strange Gods didn't they? So did the Egyptians, and yet Abraham had a child by an Egyptian (Hagar).
The Edomites continually warred with the Israelites. They hated them even during the time of Christ. However, shortly before Christ, a Maccabean Jew by the name of John Hycanus conquered and then converted the Edomites to Judaism. You would think since they hated the Jews they would only tolerate their religion as long as they were forced to, yet they ended up flourishing under it.
So much so - and to such an extent did they influence the Romans to favour them - that the Romans appointed one of them as governor of Judea, overlooking the choice of many true native Jews for the position.
They appointed Antipar (an Idumean or Edomite) to the position, and he later appointed his son Herod as King of the Jews. Herod was condemned by Christ, and killed all the first born in an attempt to kill the prophesied Messiah at birth. If this was their level of influence (through lies and corruption) in politics, you can only imagine the influence they eventually gained in the temples with the priests of Judah (the Pharisees and Saducees).
Christ said: "Beware of the leaven of the Pharisees" Leaven was always a sign or spiritual or even physical (racial ?) impurity. Shocked by this comment ? Well then you obviously haven't been reading your Bible enough now have you. Christ also said to those specific Jews who chose to reject Him :
"I know thy works, and tribulation, and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan."
~ REVELATION 2:9
"Behold, I will make them of the synagogue of Satan, which say they are Jews, and are not, but do lie; behold, I will make them to come and worship before thy feet, and to know that I have loved thee." ~ REVELATION 3:9
"Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it." John 8:44
26 "But ye believe not, because ye are not of my sheep, as I said unto you.
27 My sheep hear my voice, and I know them, and they follow me:
28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand." (John 10:26-28)
These are the Jews who crucified Christ: John 19:1-16
"1 ¶ Then Pilate therefore took Jesus, and scourged him.
2 And the soldiers platted a crown of thorns, and put it on his head, and they put on him a purple robe,
3 And said, Hail, King of the Jews! and they smote him with their hands.
4 Pilate therefore went forth again, and saith unto them, Behold, I bring him forth to you, that ye may know that I find no fault in him.
5 Then came Jesus forth, wearing the crown of thorns, and the purple robe. And Pilate saith unto them, Behold the man!
6 When the chief priests therefore and officers saw him, they cried out, saying, Crucify him, crucify him. Pilate saith unto them, Take ye him, and crucify him: for I find no fault in him.
7 The Jews answered him, We have a law, and by our law he ought to die, because he made himself the Son of God.
8 When Pilate therefore heard that saying, he was the more afraid;
9 And went again into the judgment hall, and saith unto Jesus, Whence art thou? But Jesus gave him no answer.
10 Then saith Pilate unto him, Speakest thou not unto me? knowest thou not that I have power to crucify thee, and have power to release thee?
11 Jesus answered, Thou couldest have no power at all against me, except it were given thee from above: therefore he that delivered me unto thee hath the greater sin.
12 And from thenceforth Pilate sought to release him: but the Jews cried out, saying, If thou let this man go, thou art not Caesar’s friend: whosoever maketh himself a king speaketh against Caesar.
13 When Pilate therefore heard that saying, he brought Jesus forth, and sat down in the judgment seat in a place that is called the Pavement, but in the Hebrew, Gabbatha.
14 And it was the preparation of the passover, and about the sixth hour: and he saith unto the Jews, Behold your King!
15 But they cried out, Away with him, away with him, crucify him. Pilate saith unto them, Shall I crucify your King? The chief priests answered, We have no king but Caesar.
16 ¶ Then delivered he him therefore unto them to be crucified. And they took Jesus, and led him away."
Most or maybe even all of the Jews who denied Christ were Edomite imposters and most of those who accepted Him were true Judean Jews of the line of the tribe of Judah. Those who did believe Him became known as Christians and not Jews any longer and these Edomite Jews who were particularly strong and numerous in the synagogues became the Talmudic Rabbi Jews of the Middle Ages and the Jews who also converted a half Mongoloid people (the Khazars) to Judaism - a distorted form of the belief in the God of Abraham (Jehovah or Yahweh) mixed with all sorts of anti-Christ hatred and ridiculous Dark ages customs and beliefs.
Along with the Babylonian Kabbalah being taught by their Rabbi's they form a formidable anti-Christian group today and secretly control the Christian seminaries (the "False profit" of prophesy) promoting the pro-Israeli state to the tune of millions of US dollars in voluntary and in-voluntary (tax) donations towards their cause.