There are at least 3 saints named Thecla. All were early martyrs who were never canonized because the process was not in place at the time. They were declared as saints by the early Christian community based on their martyrdom. The Orthodox Church did not exist at the time so they would have been recognized by the early Catholics. After the Orthodox Church split from from the Catholics, they continued to honor these early saints.
St. Thecla is considered a saint in the Eastern Orthodox Church and was likely venerated as a saint in the early Christian Church, although she was not officially canonized by a specific church.
Both the Roman Catholics and the Eastern Orthodox Church. She is commemorated by each of them on 23 September and 24 September, respectively.
There are a number of saints named Thecla so you need to be more specific.
There are two saints named Thecla and both died as martyrs, probably in the third or fourth century.
St. Ambrose was canonized in the early Church, likely shortly after his death in 397 AD. He is considered a Doctor of the Church and his feast day is celebrated on December 7th.
St. Agnes was declared a saint by the early Church long before the official canonization process was put into place. She was never canonized.
A canonized female is typically abbreviated as St. (Saint) if she has been officially recognized by the Catholic Church as a saint.
St. Therese of Lisieux was canonized as a saint by the Catholic Church in 1925, only 28 years after her death, due to her exemplary life of faith and virtue. She is often referred to as "The Little Flower" and is recognized for her spiritual writings and the impact of her "little way" of loving God in everyday life.
St. Joseph, the Adopted father of the Christ, was venerated as a Saint very early in the Christian Church.
Perpetua, a patrons for expectant mothers, was a martyr of the early Church. She was canonized during the Pre-Congregation during the 4th century AD.
St. Anne was Cononized in 1584 when her cult was extended to the whole church.
Roman Catholic AnswerShe wasn't, St. Amelia died and was declared a saint long before the Church's canonization process was in place. Her real name is St. Amalberga aka St. Amelia.
St. Francis Xavier was canonized with fellow missionary St. Ignatius in 1622.
St. Eligius was canonized in the Pre-Congregation era. This was when people were often canonized because of their popularity while they were alive.