Historical evidence for a separate Jewish branch of Christianity?

Can't say this is an answer but maybe more at food for thought.

A few concepts that come to mind:

1. The opening of the gospel to the gentile is in direct relationship to the rejection of the gospel by the Jews. The general rejection of the Jews to their Messiah opened the door for Gentiles to be saved. Romans 11:11-31 It begs the question of what the status of the nation of Israel is according to the gospel. I'm not talking about whether Jews can be saved but as to whether the nation of Israel is currently being proselytized. This isn't doctrine but just food for thought. There's also end time prophesy at play and the 70 weeks of Daniel. There is some teaching that we are in a stopped stage of the 70 weeks, the 69th week is frozen in time while the dispensation of grace is executed. According to this idea the Jewish nation still has the 70th week where God continues his reach to 'His people' the Jews. I'm not trying to solidify a teaching here, this is just food for thought. Remember that the Jews are originally God's 'chosen' people, not the rest of the world. God still has more work to do with the nation of Israel (the 70th week, the tribulation etc.) and this is outside of what we are currently living.

2. The church spread out in stages that Jesus prophesied of.

Acts 1:8 "But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth."

working outward from Jerusalem, then Judaea, then Samaria, then the rest of the world. One of the things I think is interesting is that none of this happened in an organized effort by the known church but as a result of exterior events that forced it to happen. Persecution, the Pentecost feast and dispersion of said visitors. Jesus builds His church according to His plan despite man's involvement or even hinderance. Do I believe in church government? Yes, absolutely. Is it centered in Israel under Jewish leadership? I don't believe that anymore than I believe that the Catholic church is the 'universal' church either. But I'm a Protestant... Lol

3. Is there a 'universal' church? The word 'Catholic' means 'universal.' Would a true universal church only exist in the context of Judaism? I think a lot of churches and denominations would disagree. Is there apostolic authority that can isolate some works from others? I can think of the instance where Paul separates from Barnabas because of Mark John and they go separate ways. Were either of them right or wrong? Paul continued a ministry evidenced by the epistles God immortalized in His word and Mark John when on to pen the gospel of Mark also immortalized in God's word.

While it was neither "Messianic Judaism" as practiced today, nor was it a group that considered itself independent of the other Gentile congregations around the world, according to reliable tradition and suggested by records and DNA, some of my ancestors were possibly members of the original Church in Jerusalem.

Though a Catholic Christian, I am of Sephardic Jewish ancestry. I grew up in what is referred to as a Crypto-Jew family, practicing long-held Jewish cultural traditions and speaking a rare Jewish language known as Ladino. While recent laws of return from Spain and Portugal have highlighted even more detail for my family about our lineage, it has been suggested by some researchers that a few members of my family line are traditionally connected to the ancient Jerusalem church.

The limited record for this group is actually part of Roman Catholic history as this church had connections to the movement that eventually divided into the Catholic West and the Orthodox East. According to this history, the last Jewish bishop of Jerusalem was Judah Kyriakos, the great-grandson of St. Jude the Apostle. When the revolt under Bar Kohba was crushed in 135 A.D./C.E., this group, which held St. James the Greater as their first bishop, disappeared.

The Sacred Liturgy of the Mass, according to tradition, originated with James the Greater, and current Catholic and Orthodox services are based on this incredibly lengthy prayer ritual which still exists in several extant versions.

The group was Christian but culturally Hebrew, or Jewish, and as such observed Torah but held faith in Christ. (Acts 21.15-26) Some members from this congregation may have been the Judaizers who caused trouble for Gentile Christians in Galatia. Members from this group, described in Scripture as those "from James," who came to visit Peter while he was there influenced the fellowship division that led to Paul's rebuke of Cephas.--Galatians 2.11-14.

However the group neither saw itself independent of the rest of the Church nor was it composed of Gentiles, being centered in Jerusalem. But exactly what happened to all the members when the revolt of 135 demolished the last Jewish communities of the era is unknown. Some of this group traditionally arrived in Seferad (Spain and Portugal) by way of Rome and lived among the Jewish community there until 1492 when the Alambra Decree expelled all Jews from Spain.

Some of the records of a few of my ancestors who suffered during the persecution of the Spanish Inquisition (the Catholic Church actually kept detailed records of the horrible things they did) have inquisitors teasing and mocking the claims of some of these victims, namely that they were of the House of David. While some of these were forced converts, some apparently were not.

After being expelled from Spain in 1492, over several generations my ancestors traveled into North Africa, crossed the Atlantic, traveled into Puerto Rico and Cuba, and eventually settled in Mexico where they founded the city now known as Monterrey. The short-lived Mexican Inquistion chased many further into South Texas, but the horrible death of one of my ancestors in Mexico who leaped to his death from a window after being cornered by inquisitors seems to have played a part in bringing the end of the Inquistion era.

It took about 20 years, but with the help of various historians, linguists, the governments of Spain and Portugal, the Catholic Church, and a number of rabbis, my family was able to assemble a history that we can trace back to Jerusalem. The stories about the Jewish Christians under St. James are choppy, limited, and incomplete however. Some of what is known is merely long-cherished tradition, hampered by centuries of persecution and struggle, but still present nevertheless.

After Paul's death, Christianity emerged as a separate religion, and Pauline Christianity emerged as the dominant form of Christianity, especially after Paul, James and the other apostles agreed on a compromise set of requirements.[Acts 15] Some Christians continued to adhere to aspects of Jewish law, but they were few in number and often considered heretics by the Church. One example is the Ebionites, who seem to have denied the virgin birth of Jesus, the physical Resurrection of Jesus, and most of the books that were later canonized as the New Testament. For example, the Ethiopian Orthodox still continue Old Testament practices such as the Sabbath. As late as the 4th century Church Father John Chrysostom complained that some Christians were still attending Jewish synagogues. https://en.wikipedia.org/wiki/Christianity_and_antisemitism

I also remember reading a work of Augustine which mentioned that Christians were still meeting in the synagogue with Jews on the Sabbath. There would be groups like the Ebionites (which may have been heretical) or Nazarenes/Netzrim which were Jewish converts who still kept the law. I would say this separation didn't become definitive until Judaism enacted a curse against them in the liturgy.

Eusebius relates a tradition, probably based on Aristo of Pella, that the early Christians left Jerusalem just prior to the war and fled to Pella beyond the Jordan River, but does not connect this with Ebionites.[11][13] They were led by Simeon of Jerusalem (d. 107) and during the Second Jewish-Roman War of 115–117, they were persecuted by the Jewish followers of Bar Kochba for refusing to recognize his messianic claims.[28]

The 12th-century Muslim historian Muhammad al-Shahrastani mentions Jews living in nearby Medina and Hejaz who accepted Jesus as a prophetic figure and followed traditional Judaism, rejecting mainstream Christian views.[34] Some scholars argue that they contributed to the development of the Islamic view of Jesus due to exchanges of Ebionite remnants with the first Muslims.[13][35] https://en.wikipedia.org/wiki/Ebionites