Many of Leonardo da Vinci's ambitious projects were never realised. His much-copied Leda and the Swan was an exception. Sadly, the painting - depicting the mythical princess Leda, who was seduced by the god Jupiter in the form of a swan - appears to have been destroyed around 1700.
Da Vinci's two preparatory sketches, however, still exist, and form the core of an impressive travelling exhibition of 10 drawings from the Royal Collection, which will be shown over the next eight months as part of the Diamond Jubilee celebrations.
In the first sketch, Leda looks downwards, devoid of expression. Martin Clayton, curator of the exhibition, says Da Vinci's treatment of the subject was relatively demure. (It has long been debated whether the mating was consensual or rape, and other artists of the period produced very graphic images.)
Da Vinci's work, however, is most notable for Leda's complicated hairstyle, reflecting his love of adornment, elaborate headdresses and tightly braided and knotted coiffures.
The second drawing appears remote from the first. It focuses on a sprig of oak (Quercus robur) and one of dyer's greenweed (Genista tinctoria), a species of broom with yellow flowers. Drawn with finely pointed red chalk on paper coated with a delicate orange-brown preparation, the page appears to have been folded - perhaps into Da Vinci's notebook.
It was through drawing that Da Vinci attempted to record and understand the world around him. So it seems fitting that these, and his other sketches, continue to instruct and inform young people on how to do the same.
Did you know?
Da Vinci was left-handed and habitually wrote his personal notes in mirror-image, from right to left. It has been claimed that this was an attempt to keep his investigations secret, but modern scholars believe it was a childhood trick he never abandoned. Get your class to try it.
Ten Drawings by Leonardo da Vinci: A Diamond Jubilee Celebration will be touring until 20 January 2013. The exhibition is currently on display at Bristol Museum and Art Gallery. www.bristol.gov.ukpageten-drawings-leonardo-da-vinci-exhibition
Explore more of Leonardo da Vinci's work on the Royal Collection microsite.
Follow Da Vinci's life story and discover his artistic technique with BBC Learning Zone.
Help pupils emulate his style with a lesson from nut.
In the forums
Art teachers share their ideas for lessons on Da Vinci.
Find all links and resources at www.tes.co.ukresources033.