Wikipedia states that the publication of works by secular historians in the mid-19th century appear to have sparked widespread public efforts to ask the Church to officially canonize her.
Catholic-Pages states: In official Church procedures there are three steps to sainthood: one becomes Venerable, Blessed and then a Saint. Venerable is the title given to a deceased person recognized as having lived heroic virtues. To be recognized as a blessed, and therefore beatified, in addition to personal attributes of charity and heroic virtue, one miracle, acquired through the individual's intercession, is required. Canonization requires two, though a Pope may waive these requirements. Martyrdom does not usually require a miracle.