Did early Christian converts follow Kosher?
Possibly, but it may might be unprovable with historical sources.
Certainly Jewish converts would have continued with their dietary requirements which would have been acceptable in the Early Church.
Pagan converts soon outnumbered Jewish converts. It would seem that the dishes on the table of the members of most of the Early Christian communities were similar to those of their pagan neighbors. The anonymous author of the “Epistle to Diognetus” (150 AD.) – one of the first Christian texts that reached us, said: “As for excessive daintiness of Jews in food … – all this is so ridiculous and not worth a word … (Christians) living in Hellenic and barbarian cities follow the customs of those inhabitants … in food and in everything else. ” Tertullian (an early Christian apologist) echoed him: “… (Christians) live with you, … use the same food, the same clothes, they have the same household and the same everyday needs.” The Early Christians did not do any thing to stand out in custom, dress or diet! They tried to blend in as best as possible in order to avoid persecution.
4:1 But again their [Jewish] scruples concerning meats, and their superstition relating to the sabbath and the vanity of their circumcision and the dissimulation of their fasting and new moons, I do [not] suppose you need to learn from me, are ridiculous and unworthy of any consideration.
5:1 For Christians are not distinguished from the rest of mankind either in locality or in speech or in customs.
5:2 For they dwell not somewhere in cities of their own, neither do they use some different language, nor practise an extraordinary kind of life.
5:3 Nor again do they possess any invention discovered by any intelligence or study of ingenious men, nor are they masters of any human dogma as some are.
5:4 But while they dwell in cities of Greeks and barbarians as the lot of each is cast, and follow the native customs in dress and food and the other arrangements of life, yet the constitution of their
own citizenship, which they set forth, is marvellous, and confessedly contradicts expectation.
5:5 They dwell in their own countries, but only as sojourners; they bear their share in all things as citizens, and they endure all hardships as strangers. Every foreign country is a fatherland to them, and every fatherland is foreign.
The only possible community to follow a truly kosher diet since Apostolic Times would be the Christian communities in Ethiopia. The other Christian communities which soon Out numbered the Jewish converts most certainly did not follow kosher dietary laws.
There may not any historical evidence at hand, but the Ethiopian Orthodox Tewahedo Church, follows a very ancient tradition of observing many ancient Jewish Biblical kosher laws as prescribed in the Old Testament. There is no reason to presume that their traditions did not start in themselves in the Early Church. This may have been because of their isolation in regards to other Christian communities at that time and their closeness to the Jewish communities in Ethiopia.
Conversions in Ethiopia grew so rapidly in the first few centuries of [Christendom] (https://en.m.wikipedia.org/wiki/Christianization) that in 325 A.D., the Kingdom of Aksum (Modern Ethiopia and Eritrea) became the second country to declare Christianity as its official state religion after Armenia. To this day believers of the Ethiopian Church requires that one follows a kosher diet in some stricter than that of some Jewish communities.
Ethiopian Orthodox Tewahedo Church
Many traditions claim that Christian teachings were introduced to the region immediately after Pentecost. John Chrysostom speaks of the "Ethiopians present in Jerusalem" as being able to understand the preaching of Peter in Acts 2:38. Possible missions of some of the Apostles in the lands now called Ethiopia is also reported as early as the 4th century. Socrates of Constantinople includes Ethiopia in his list as one of the regions preached by Matthew the Apostle, where a specific mention of "Ethiopia south of the Caspian Sea" can be confirmed in some traditions such as the Roman Catholic Church among others. Ethiopian Church tradition tells that Bartholomew accompanied Matthew in a mission which lasted for at least three months. Paintings depicting these missions can be seen in the Church of St. Matthew found in the Province of Pisa, in northern Italy portrayed by Francesco Trevisan (1650–1740) and Marco Benefial (1688–1764).
The earliest account of an Ethiopian converted to the faith in the New Testament books is a royal official baptized by Philip the Evangelist (distinct from Philip the Apostle), one of the seven deacons (Acts, 8:26–27):
Then the angel of the Lord said to Philip, Start out and go south to the road that leads down from Jerusalem to Gaza. So he set out and was on his way when he caught sight of an Ethiopian. This man was a eunuch, a high official of the Kandake (Candace) Queen of Ethiopia in charge of all her treasure. (Acts, 8:26–27)
The passage continues by describing how Philip helped the Ethiopian treasurer understand a passage from the Book of Isaiah that the Ethiopian was reading. After Philip interpreted the passage as prophecy referring to Jesus Christ, the Ethiopian requested that Philip baptize him, and Philip did so. The Ethiopic version of this verse reads "Hendeke" (ህንደኬ); Queen Gersamot Hendeke VII was the Queen of Ethiopia from c. 42 to 52. Where the possibility of gospel missions by the Ethiopian eunuch cannot be directly inferred from the Books of the New Testament, Irenaeus of Lyons around 180 AD writes that "Simon Backos" preached the good news in his homeland outlining also the theme of his preaching as being the coming in flesh of God that "was preached to you all before." The same kind of witness is shared by 3rd and 4th century writers such as Eusebius of Caesarea and Origen of Alexandria.
Early Christianity became the established church of the Ethiopian Axumite Kingdom under king Ezana in the 4th century when priesthood and the sacraments were brought for the first time through a Syrian Greek named Frumentius, known by the local population in Ethiopia as "Selama, Kesaté Birhan" ("Father of Peace, Revealer of Light"). As a youth, Frumentius had been shipwrecked with his brother Aedesius on the Eritrean coast. The brothers managed to be brought to the royal court, where they rose to positions of influence and baptized Emperor Ezana. Frumentius is also believed to have established the first monastery in Ethiopia, named Dabba Selama after him. In 2016, scientists excavated a 4th-century AD basilica (radio-carbon dated) in northeastern Ethiopia at a site called Beta Samati. This is the earliest known physical evidence of a church in sub-Saharan Africa.
The faith and practice of Orthodox Ethiopian Christians include elements from Miaphysite Christianity as it has developed in Ethiopia over the centuries. Christian beliefs include belief in God (in Ge'ez / Amharic, ′Egziabeher, lit. "Lord of the Universe"), veneration of the Virgin Mary, the angels, and the saints, besides others. According to the Ethiopian Orthodox Church itself, there are no non-Christian elements in the religion other than those from the Old Testament, or Higge 'Orit (ሕገ ኦሪት), to which are added those from the New Testament, or Higge Wongiel (ሕገ ወንጌል). A hierarchy of Kidusan/ቅዱሳን (angelic messengers and saints) conveys the prayers of the faithful to God and carries out the divine will, so when an Ethiopian Christian is in difficulty, he or she appeals to them as well as to God. In more formal and regular rituals, priests communicate on behalf of the community, and only priests may enter the inner sanctum of the usually circular or octagonal church where the tabot ("ark") dedicated to the church's patron saint is housed. On important religious holidays, the tabot is carried on the head of a priest and escorted in procession outside the church. It is the tabot, not the church, which is consecrated. At many services, most parish members remain in the outer ring, where debteras sing hymns and dance.
Similarities to Judaism and Islam
The Ethiopian Church places a heavier emphasis on Old Testament teachings than one might find in Eastern Orthodox, Roman Catholic or Protestant churches, and its followers adhere to certain practices that one finds in Orthodox or Conservative Judaism. Ethiopian Christians, like some other Eastern Christians, traditionally follow dietary rules that are similar to Jewish Kashrut, specifically with regard to the slaughter of animals. Similarly, pork is prohibited, though unlike Rabbinical Kashrut, Ethiopian cuisine does mix dairy products with meat, which in turn makes it even closer to Karaite and Islamic dietary laws (see Halal). Women are prohibited from entering the church temple during menses; they are also expected to cover their hair with a large scarf (or shash) while in church, as described in 1 Corinthians, chapter 11. As with Orthodox synagogues, men and women sit separately in the Ethiopian church, with men on the left and women on the right (when facing the altar). (Women covering their heads and separation of the sexes in churches officially is common to some other Christian traditions; it is also the rule in some non-Christian religions, Islam and Orthodox Judaism among them).
Before praying, they wash their hands and face in order to be clean before and present their best to God; shoes are removed in order to acknowledge that one is offering prayer before a holy God. Ethiopian Orthodox worshipers remove their shoes when entering a church temple, in accordance with Exodus 3:5 (in which Moses, while viewing the burning bush, was commanded to remove his shoes while standing on holy ground). Furthermore, the Ethiopian Orthodox Tewahedo Church upholds Sabbatarianism, observing the seventh-day Sabbath (Saturday), in addition to the Lord's Day (Sunday), although more emphasis, because of the Resurrection of Christ, is laid upon Sunday.
The Ethiopian Orthodox Church calls for male circumcision, with near-universal prevalence among Orthodox men in Ethiopia. The Ethiopian Orthodox practice circumcision as a rite of passage, and they circumcise their sons "anywhere from the first week of life to the first few year".
The Ethiopian Orthodox Church prescribes several kinds of hand washing and traditionally follow rituals that are similar to Jewish netilat yadayim, for example after leaving the latrine, lavatory or bathhouse, or before prayer, or after eating a meal. The Ethiopian Orthodox Church observes days of ritual purification. People who are ritually unclean may approach the church but are not permitted to enter it; they instead stand near the church door and pray during the liturgy.
Interesting note also is that in Ethiopia, the new day starts at sundown, just as the Jewish tradition holds to this day!
Because Ethiopia is close to the Equator, daylight is pretty consistent throughout the year. So many Ethiopians use a 12-hour clock, with one cycle of 1 to 12 — from dawn to dusk — and the other cycle from dusk to dawn.
Most countries start the day at midnight. So 7:00 a.m. in East Africa Time, Ethiopia's time zone, is 1:00 in daylight hours in local Ethiopian time. At 7:00 p.m., East Africa Time, Ethiopians start over again, so it's 1:00 on their 12-hour clock. - If you have a meeting in Ethiopia, you'd better double check the time
The Ethiopian Church also claims that one of its churches, Our Lady Mary of Zion, is host to the original Ark of the Covenant that Moses carried with the Israelites during the Exodus.
Church of Our Lady Mary of Zion
Some years ago, I had the grace to encounter many Ethiopian priests that were traveling through our area and I assure you that they firmly believe that their dietary traditions go back to the very foundations of their Church. They see no reason to change their traditions... Nevertheless, they did not criticize others for their dietary rules or etiquette.
In the end, no one will be able find a source from the Early Church history that forbids non-kosher meat, since it is not immoral to follow such a tradition. Certainly Jewish converts would naturally keep to this biblical tradition. But after Peter’s vision of Acts 10:11 (Peter's vision of a sheet with animals) non kosher foods were permitted. One would be hard pressed to prove this last point one way or anther. Kosher dietary laws are not mentioned in historical records from that time frame. Nowhere will one find that the kosher diet was an obligation in the Early Church.
The traditional view is that the kosher laws are not applicable to the Church. It is pointed out that the Jewish leaders of the Early Church simply settled on three recommendations for Gentile believers, link: to abstain from things polluted by idols, from things strangled, and from blood (Acts 15:19,20). Today, believers have died with Christ, and those who have died are not bound by the Law. To quote Paul:
For sin shall not be master over you, for you are not under law, but under grace (Rom 6:14)
But what law is Paul referring to? The Ten Commandments are essentially a summary of the entire Old Testament law. Apart from the fourth commandment (remembering the Sabbath day), the other nine commandments are repeated in the New Testament, and the greatest of these is to love God (Mat 22:37-38). Now loving God means keeping His word (Jn 14:23), and Leviticus 11 is God’s word. As we have seen, the food laws were given to Israel as a daily reminder to be holy, and they did this by avoiding things not designed by God for human consumption. So why shouldn’t the church follow the same wisdom? If the church rejects God’s words of wisdom, is she still loving God?
That said, most Christians still reject kosher and quote well-known NT texts in their defence. - Kosher Laws and Christianity
Let us recall that upon leaving the Ark, God told Noah that every moving thing that lives could be eaten (Gen 9:3). Did this mean that Noah could now eat the offspring of the animals God had previously declared to him as unclean (Gen 7:2)? Was Noah now permitted to consume snails and mice and sit down to roast pig – creatures declared as unclean in Lev 11 and Deut 14?
Let us remember that the edible dormouse (Glis glis) was considered a delicacy in ancient Rome, either as a savoury appetizer or as a dessert (dipped in honey and poppy seeds). The Romans used a special kind of enclosure, a glirarium, to raise and fatten dormice for the table.