The painting today (left) and an artist's impression of how the snake may have originally looked
A mysterious image of a coiled snake has appeared in a 16th century painting of Queen Elizabeth I, the National Portrait Gallery has said.
The Tudor queen was depicted with the snake clasped in her fingers in an original version of the work, but it was replaced with a bunch of roses.
The paint has deteriorated over the years to reveal the serpent's outline.
The painting will go on display at the London gallery on 13 March for the first time since 1921.
It will form part of the Concealed and Revealed: The Changing Faces of Elizabeth I exhibition, which runs until 26 September.
The portrait was created by an unknown artist in the 1580s or early 1590s.
The gallery suggested the snake's removal may have been due to the ambiguity of the emblem. It may have represented wisdom, but snakes are also linked to notions of Satan and original sin.
Dr Tarnya Cooper, of the Making Art in Tudor Britain project, said: "The recent technical analysis on these remarkable portraits has been critical to our understanding of Tudor painting.
"The portrait of Elizabeth I with a hidden serpent is a really unusual survival. Yet, it is difficult to know exactly why the serpent may have been originally included, or how common this motif might have been.
"The queen certainly owned jewellery and costume including emblems of serpents, which were probably understood as a symbol of wisdom. However no other portrait of Elizabeth appears to depict her holding a snake.
"The current condition of the picture has meant it has not been on display for decades, and this display provides an exciting opportunity to present it to the public alongside other key portraits."