This may have caused some pondering with you all, but it is strongly believed by some that Leonardo Da Vinci was vegetarian, perhaps even vegan, and this comes from letters, written in his own hand, which you can read more about at many sites, including The International Vegetarian Union and Bitesize Vegan
I imagine he would not have been too happy to realise his person was being used to encourage the purchase of Liebig cards, which were issued with meat extract, including this one
Strangely other than Liebig, he is seldom featured on cards – though he is on British American Tobacco Domino brand “Figures Historiques” second series (B705-556.2 ~1961) 6/25 – and on Brooke Bond tea “Inventors and Inventions” (1975) 6/50. His great work, the Mona Lisa, fares a little better, for she appears on W.D. & H.O. Wills “Art Photogravures” (W675-550 : W62-397 : W/43 ~ 1912/13) 5/50 – R & J Hill “Famous Pictures” (H554-335 : H46-26 : H.468 ~1913) 2/25 - John Player “Miniatures” (P644-230 : P72-111 : RB.17/127 ~ June 1923) 1/25 - and on Coopers Tea “Mysteries and Wonders of the World” second series of 25 (1961) number 35 (the mystery and wonder being that her eyes seem to follow you around the gallery as you walk).
Then there is a rather weird one, Barratt “Merchant Ships of the World” blue back (1962) where card 24/25 is the S.S. Leonardo da Vinci. There were several ships by this name but the text tells us our one was the latest addition to the Italia Line, making her maiden voyage on June 30, 1960, and being the largest liner built in Italy since the last war. This makes her the replacement for the SS Andrea Doria, which collided with the MS Stockholm on July 25, 1956.
Our original Godfrey Phillips reference book, RB.13, dating from 1949, and originally costing 8/6d, tells us that this set is “small cards, size 67 x 37 m/m. Fronts printed by letterpress in colour. Backs in brown, with descriptive text, adhesive. Issued 1936”
These were similar to the Phillips set of “Famous Boys” (P521-320 : P50-57 : Ph/63 ~ 1924)