A plot is afoot to murder the Medici's, members of the Pazzi (a banking family) family plot a conspiracy to assassinate Lorenzo de' Medici and his brother Giuliano to oust the Medici family as rulers of Florence. One of the Medici's survives and exacts revenge on the Pazzi family. Lorenzo survives and is out for revenge. Most of the conspirators were soon caught and executed; five, including Francesco de' Pazzi, were hanged from the windows of the Palazzo della Signoria. Five women, all friends, and artists, have to paint in secret and when one of the women disappears, supposedly also stealing a picture, they need to figure out what happened to her. They find out that the picture that is missing is a painting of the conspiracy and who was involved. To protect their friend, they set out to paint another painting like the first one. They all have sketches and with the help of Leonardo da Vinci, they create this painting. The women have to paint in secret as it is against the law for a woman to paint. Renaissance Florence is a conflicted place to live as the Medici's are large and in charge. As Portrait of Conspiracy continues the reader learns more about each of the women and how the strength of all of them, bring the men involved in the conspiracy to justice, all without the Medici's knowledge. A passage at the end of the book caught my eye and it is "Together, there is not a greater power than the strength of women bound to each other." A very true statement and one that these women firmly believe. I enjoy this time period in history in Europe, a time when women's worth depended on their dowry and whether they can give their husband's heirs. I love a story with a strong woman as the protagonist, but in this historical novel, there were five. Plus it was interesting learning about Leonardo da Vinci who played a big part also. This novel was very well researched and told about an actual conspiracy that took place in Medici's Florence.