 Catherine watched the development of the Encyclopédie project with great interest and expressed affection for French Enlightenment philosophie overall. Fate provided her with an occasion to express her appreciation directly to Diderot when a financial burden forced him to sell his library. Catherine made the purchase, giving Diderot an annual pension in addition. This made him a wealthy man for the rest of his life. Diderot traveled to St. Petersburg to meet with Catherine in 1773–74, and this trip marks his entrance into a leisured retirement in Paris where he continued to write.