He was given a very important commission. The Signoria (Town Council) of the City of Florence wanted two large frescos painted on the walls of the most important room of the Signoria Palace. Michelangelo was to paint "The Battle of Cascina" and Leonardo was to paint "The Battle of Anghiari". Leonardo began the project by studying and drawing the faces of angry men and fighting horses. These drawings can still be seen in his notebooks. But unfortunately, this was to be another failure for Leonardo. When he painted the picture on the wall, instead of using fresco, he mixed the paints with oil. The paint would not dry. Leonardo lit some fires to dry it, and the painting melted. Peter Paul Rubens drew a copy of the middle part. After a time, the town council covered it up and got somebody else to paint the wall. Michelangelo did not finish his painting either, because the Pope called him to Rome.
In about 1503 Leonardo began painting the portrait of a woman known as "Mona Lisa", the most famous portrait that has ever been painted. He continued working on it for many years. It is a small picture, painted in oil on a wooden panel. It shows the face, upper body and hands of a woman. She is very plainly dressed. For a portrait, a woman would usually put on her best clothes and jewellery. Mona Lisa has a dark dress and a fine black veil over her head. Leonardo often left symbols in his paintings that give clues about the person. The unusual thing about this picture is the smile. The smile is the clue to her name: Mona Lisa Giacondo. Giacondo means "the joking one". (Mona is short for Madonna which means "My Lady".)
The reason why the painting is so famous is that it seems to be full of mystery. Mona Lisa's eyes look out at the viewer. But no-one can guess what she is thinking. Her eyes and her mouth seem to be smiling. This is very unusual in a portrait painting. Most people in portraits look very serious. It is hard to tell what Mona Lisa's exact expression is. When a person wants to read another person's feelings, they look at the corners of their mouth and eyes. But Leonardo has painted soft shadows in the corners of Mona Lisa's mouth and eyes, to disguise her expression. The soft shadows are also found on the sides of her face, her neck and hands. The way that Leonardo uses shadow is called "sfumato" (which is an Italian word for "smoke"). Vasari said that the picture was so beautifully painted that every other artist who looked at it thought that they could never paint so well.
In 1506, Leonardo went back to Milan with his pupils, and lived in his own house in Porta Orientale. D'Oggione made several copies of the "Last Supper". Luini made a copy of "the Virgin of the Rocks". Boltraffio (and the others) painted many Madonna and Child pictures which can still be seen in art galleries and churches. One of pupils was a young nobleman called Count Francesco Melzi. Melzi never became a very good painter, but he loved Leonardo and stayed with him until the day he died.
In September 1513 Leonardo went to Rome and lived there until 1516. He lived in the Vatican. The three greatest painters of the High Renaissance, Leonardo, Michelangelo and Raphael were all working in Rome at the same time. Even though their names are often said together as if they were friends, they were not. Leonardo at this time was in his sixties, Michelangelo was middle-aged. He was not friendly to either Leonardo or Raphael. Raphael was a very clever young painter who learnt a lot by looking at the pictures painted by Leonardo and Michelangelo. But neither of them was ever his teacher.
In October 1515, King Francis I of France captured Milan. On December 19, there was a meeting of Francis I and Pope Leo X, in Bologna. Leonardo went to the meeting with Pope Leo.
Leonardo made an amazing toy to entertain King Francis. It was a life-sized mechanical lion that could walk. It had doors in its chest which opened, and a bunch of lilies came out. Lilies were the royal symbol of the French Kings.
In 1516, Francis I invited Leonardo to go to France with him. He gave Leonardo a beautiful house called "Clos Lucé" (sometimes called "Cloux"). It is near the king's palace, Chateau Amboise. Leonardo spent the last three years of his life at Clos Lucé, with his faithful friend and apprentice, Count Melzi. The king gave Leonardo a pension of 10,000 scudi. One of the last paintings that Leonardo did was a picture of "John the Baptist". His model was Salai, with his beautiful long curling hair.
When Leonardo was dying, he asked for a priest to come, so that he could make his confession and receive Holy Communion.
Leonardo died at Clos Lucé, on May 2, 1519. King Francis had become a close friend. Vasari says that the King held Leonardo's head in his arms as he died. In his will, he asked that sixty beggars should follow his casket in procession. He was buried in the Chapel of the Chateau Amboise.
Leonardo had never married and had no children of his own. In his will, he left his money, his books and most of his paintings to Count Melzi. Leonardo also remembered his other pupil Salai and his servant Battista di Vilussis, who each received half of Leonardo's vineyards near Milan. Leonardo's left to his serving woman a black cloak with a fur edge. Salai was the owner of Leonardo's most famous oil painting, the "Mona Lisa". He still owned it a few years later when he died, after fighting in a duel.
King Francis said: "There had never been another man born in the world who knew as much as Leonardo, not so much about painting, sculpture and architecture, as that he was a very great philosopher."
Leonardo did not paint very many pictures. But he drew hundreds of quick sketches, plans, maps and detailed drawings. This is the way that he recorded all the interesting things that he saw, studied and thought about.
Some of Leonardo's drawings are "studies" for paintings. In these drawings Leonardo planned the things he was going to paint. Some studies are plans for whole paintings. One of these paintings is the large beautiful drawing of the Madonna and Child with St Anne and St John the Baptist that is now in the National Gallery, London.
Many of the studies show "details" that Leonardo wanted to get just right. One study shows a very detailed perspective drawing of the ruined buildings in the background of the painting of the Magi. Other studies show hands, faces, drapery, plants, horses and babies.
The earliest drawing by Leonardo that has a date on it, is a "Landscape of the Arno Valley", 1473, which shows the river, the mountains, Montelupo Castle and the farmlands beyond it in great detail.
Leonardo studied things all his life. He did not go to university to study. He studied by looking at things in the world around him. He looked at things to see how they were made and how they worked. He drew the things that he saw and the discoveries that he made into his notebooks, and made notes about them. Many of his notebooks are now in museums. There are 13,000 pages of notes and drawings. Many of these are scientific studies.
Leonardo's notebooks are hard to read because he wrote backwards in "mirror writing". Some people think that perhaps he was trying to keep his work secret. This is not true. Leonardo wrote (and sometimes drew) with his left hand. In those days pens were made from a quill (a large feather) that was cut with a pen-knife on the end. It is hard for a left-handed person to write with a quill in the ordinary way, but quite easy to write backwards.
It is likely that Leonardo planned to publish the studies in his notebooks. He organized many pages carefully, with one study taking up the front and back of each page. There is a page with drawings and writing about the human heart and a page about the womb and the fetus. One page shows drawings of the muscles of a shoulder and another page shows how an arm works.