According to the traditional story, Catherine was the daughter of Costus, a pagan governor of Alexandria, where she was born.  She is said to have announced to her parents that she would only marry someone who surpassed her in beauty, intelligence, wealth, and social status. This has been interpreted as an early foreshadowing of her eventual discovery of Christ. “His beauty was more radiant than the shining of the sun, His wisdom governed all creation, His riches were spread throughout all the world.” Though raised a pagan, she converted to Christianity in her late teens. It is said that she visited her contemporary, the Roman Emperor Maximinus Daia, and attempted to convince him of the moral error in persecuting Christians. She succeeded in converting his wife, the Empress, and many pagan philosophers whom the Emperor sent to dispute with her, all of whom were subsequently martyred. Upon the failure of the Emperor to win Catherine over, he ordered her to be put in prison; and when the people who visited her converted, she was condemned to death on the breaking wheel, an instrument of torture. According to legend, the wheel itself broke when she touched it, so she was beheaded.

According to Christian tradition, angels carried her body to Mount Sinai, where, in the 6th century, the Eastern Emperor Justinian established Saint Catherine’s Monastery, Mount Sinai, the church being built between 548 and 565 in Saint Catherine, Egypt, on the Sinai peninsula. Saint Catherine’s Monastery survives, a famous repository of early Christian art, architecture and illuminated manuscripts that is still open to visiting scholars. The historian Harold T. Davis says that Catherine’s story dates only from the 10th century AD, and that “assiduous research has failed to identify Catherine with any historical personage”; Davis suggests that the invention of Catherine may have been inspired by the story of the martyred pagan philosopher Hypatia of Alexandria. She did certainly form an exemplary counterpart to Hypatia in the medieval mindset; and it has been suggested that she was invented specifically for that purpose. Like Hypatia, she is said to have been highly learned (in philosophy and theology), very beautiful, sexually pure, and to have been brutally murdered for publicly stating her beliefs. The story of Catherine is placed a hundred years before Hypatia’s death, but there are no contemporary sources for her life.

Because of the fabulous character of the account of her martyrdom and the lack of reliable documentation, the Roman Catholic Church in 1969 removed her feast day from the Calendar. But she continued to be commemorated in the Roman Martyrology on November 25. In 2002, her feast was restored to the General Roman Calendar as an optional memorial.

The 1908 Catholic Encyclopedia describes the historical importance of the belief in her as follows:

Ranked with St Margaret and St Barbara as one of the fourteen most helpful saints in heaven, she was unceasingly praised by preachers and sung by poets. It is believed that Jacques-Benigne Bossuet dedicated to her one of his most beautiful panegyrics and that Adam of St. Victor wrote a magnificent poem in her honour: Vox Sonora nostri chori, etc. In many places her feast was celebrated with the utmost solemnity, servile work being suppressed and the devotions being attended by great numbers of people. In several dioceses of France it was observed as a Holy Day of Obligation up to the beginning of the seventeenth century, the splendor of its ceremonial eclipsing that of the feasts of some of the Apostles. Numberless chapels were placed under her patronage and her statue was found in nearly all churches, representing her according to medieval iconography with a wheel, her instrument of torture. Meanwhile, owing to several circumstances in his life, Saint Nicholas of Myra was considered the patron of young bachelors and students, and Saint Catherine became the patroness of young maidens and female students. Looked upon as the holiest and most illustrious of the virgins of Christ after the Blessed Virgin Mary, it was natural that she, of all others, should be worthy to watch over the virgins of the cloister and the young women of the world. The spiked wheel having become emblematic of the saint, wheelwrights and mechanics placed themselves under her patronage. Finally, as according to tradition, she not only remained a virgin by governing her passions and conquered her executioners by wearying their patience, but triumphed in science by closing the mouths of sophists, her intercession was implored by theologians, apologists, pulpit orators, and philosophers. Before studying, writing, or preaching, they besought her to illumine their minds, guide their pens, and impart eloquence to their words.  At the  beginning of the fifteenth century, it was rumored that she had spoken to Joan of Arc and, together with St. Margaret, had been divinely appointed Joan’s adviser.