Feast Of Saint Thomas The Apostle - 21 December

Quoted from The Free Dictionary [1]:

The Feast of St. Thomas the Apostle, established in the twelfth century, originally fell on December 21, the day of the winter solstice. Folk customs attached to the saint's day, therefore, reflected both the occurrence of the solstice and the closeness of Christmas. Although the Roman Catholic Church has since moved St. Thomas's Day to July 3, some Anglicans preserve the December date. The Greek Orthodox Church celebrates the saint's feast on October 6.

Life and Legends of St. Thomas the Apostle

Jesus selected Thomas as one of his twelve disciples. Although he appears in all four Gospels, he is perhaps best remembered as the apostle who questioned the truth of Jesus' resurrection because he had not seen the risen Jesus with his own eyes (John 20:25). In so doing he earned the nickname "Doubting Thomas." In the Greek used by the writers of the New Testament, his name means "twin."

According to legend, St. Thomas spread the gospel to the East, venturing as far as India in his quest. There he established a Christian community in the southwestern region known then as Malabar, currently part of the state of Kerala. One story claims that Thomas found and baptized the Three Kings (see also Magi). These three then became India's first bishops. Another tale reports that an Indian king commissioned Thomas to build an opulent palace. Instead, the saint took the money entrusted to him for the project and distributed it to the poor. He died a martyr's death and was buried in Mylapore, near the city of Madras.

Artists often depicted the saint kneeling by the side of the risen Christ, verifying Jesus' identity by touching his wounds. Artists have also portrayed him holding a carpenter's rule. In medieval times he was known as the patron saint of architects, masons, and stonecutters. St. Thomas also protects the aged.

[1] https://encyclopedia2.thefreedictionary.com/St.+Thomas%27s+Day#:~:text=The%20Feast%20of%20St.%20Thomas%20the%20Apostle%2C%20established,of%20the%20solstice%20and%20the%20closeness%20of%20Christmas., bold italics original.