I came across this on the St Thomas Christians which is very interesting so I wanted to see if anyone had more details about them..
"When 16th century European priests arrived in southern India to introduce Christianity, they were told that a more famed Christian missionary had been there first. In the districts of Travancore and Cochin, there was already a community of Indian Christians with a tradition of loose communion with the Roman Catholic Church. The man who first converted them, the Indians said, was none other than St. Thomas the Apostle (the "Doubting Thomas"), who reputedly arrived in India aboard a Roman trading vessel in 52 A.D.

Whether St. Thomas actually preached under the palm trees of Travancore and Cochin is a point that historians have neither proved nor disproved. But nowadays there are 2,357,000 Indian Christians in the area, and for the past month, giving St. Thomas the benefit of the doubt, they have been celebrating the 1900th anniversary of his landing.

Three Drops of Honey. According to tradition, St. Thomas made his first conversions by a miracle. At the village of Palur, he found some Brahman priests throwing handfuls of water into the air as they performed their purification prayers. Thomas threw some water into the air himself, and it hung suspended in the form of sparkling flowers. Tradition continues that most of the Brahmans embraced Christianity on the spot, and that the rest fled. To this day, no orthodox Brahman will take a bath in Palur.

Although St. Thomas was later killed (one legend says he was pierced by spears), the religion founded by him or later missionaries took firm hold. By the sixth century there were Indian churches in contact with the Christian bishops of Syria. In 883, King Alfred the Great sent an English bishop to make an offering for him at St. Thomas' shrine in Mylapore. But contact with the West was precarious, and by the end of the Middle Ages the Indian church was practically forgotten.

In their isolation, the Indians developed surprisingly few originalities of dogma. But they did intersperse their religious rites with local Hindu practices. Like Hindus, Indian Christian women have always worn large gold earrings in the upper part of their ears. The Christians preserve Hindu-style observances for birth, marriage and death, e.g., when a child is born, its father pours into its mouth three drops of honey in which gold has been dipped.

Festive Coconuts. The Portuguese, during their rule in India, tried to stamp out native Christian practices and enforce strict conformity to Latin rituals. In reaction, many Indian Christians broke away from Rome. Called "Jacobites," after Jacob al-Baradai, a 6th century Syrian bishop, they now number 800,000. Another group, the St. Thomas Christians (membership: 200,000), broke away in turn from the Jacobites, under Protestant influence, in 1837. About 1,000,000 "Romo-Syrians" have remained faithful to the Roman Catholic Church, although they use Syriac and their native language in their liturgy."
https://content.time.com/time/subscriber/article/0,33009,817710,00.html

Interesting. I've never heard of this before.

Have you ever heard of the antiquities of the Cherokees?. There were Sabbath keepers among them when the first white men reached them and early in the history of the US. They also had legends of a world wide flood and knew the story of the children of Israel and Moses.

]url] https://ualrexhibits.org/tribalwriters/artifacts/Antiquities-Cherokee-Indians.html [/url]

Here is even more on this..
"The St. Thomas Christians of Kerala, India, believe that Thomas the apostle took Christianity to India. Their
very existence bears witness to it.Thomas is reported to have arrived in Kerala in A.D.
52. He preached among the settled Jews and Hindus and established churches.

The St. Thomas Christians practiced a simple faith as taught by the apostle. They had two sacraments, baptism and
Lord's Supper, and they worshiped only on Saturday at least until the fourth century. They followed the Syriac liturgy.
Until the sixteenth century they had ties with East Syrian (Persian) churches. They continued their Sabbath observance
throughout this period.

In the sixteenth century the St. Thomas Christians came into contact with the Roman Catholics. The subsequent
establishment of the Inquisition and the Latinization program led to the Synod of Diamper (1599) and later to the
Humbled Cross Oath in 1653. After the St. Thomas Christians came under Roman Catholicism, the church began to fracture."
Heritage of the St. Thomas Christians