The feast day for St. Leocadia of Toledo appears under 9 December in the historical martyrologies of the ninth century.

[2] In the first half of the seventh century "the church of Saint Leocadia" was mentioned as the meeting-place of the Fourth Synod of Toledo in 633, as well as of the fifth in 636, and the sixth in 638.

[2] Of her veneration, the Catholic Encyclopedia writes that "long before that date, therefore, Leocadia must have been publicly honoured as a martyr.

There is no doubt of the historical fact of her martyrdom, whilst the date of 9 December for her annual commemoration obviously rests on the tradition of the Church of Toledo.

Fernando Álvarez de Toledo, 3rd Duke of Alba attempted unsuccessfully to rescue the rest of her relics.

Philip II of Spain presided over a solemn ceremony commemorating the final translation of her relics to Toledo, in April 1587.