Darwin had his basic theory of natural selection "by which to work" by December 1838, yet almost twenty years later, when Wallace's letter arrived on 18 June 1858, Darwin was still not ready to publish his theory. It was long thought that Darwin avoided or delayed making his ideas public for personal reasons. Reasons suggested have included fear of religious persecution or social disgrace if his views were revealed, and concern about upsetting his clergymen naturalist friends or his pious wife Emma. Charles Darwin's illness caused repeated delays. His paper on Glen Roy had proved embarrassingly wrong, and he may have wanted to be sure he was correct. David Quammen has suggested all these factors may have contributed, and notes Darwin's large output of books and busy family life during that time.
Why might Darwin have postponed publishing his theory of evolution for over 20 years?
fear of religious persecution or social disgrace

The situation became so tense that war with the United States seemed imminent. On April 22, 1914, on the initiative of Felix A. Sommerfeld and Sherburne Hopkins, Pancho Villa traveled to Juarez to calm fears along the border and asked President Wilson's emissary George Carothers to tell "Senor Wilson" that he had no problems with the American occupation of Veracruz. Carothers wrote to Secretary William Jennings Bryan: "As far as he was concerned we could keep Vera Cruz [sic] and hold it so tight that not even water could get in to Huerta and . . . he could not feel any resentment". Whether trying to please the U.S. government or through the diplomatic efforts of Sommerfeld and Carothers, or maybe as a result of both, Villa stepped out from under Carranza's stated foreign policy.
Pancho Villa seeked a conversation with which American President?
President Wilson

Modern standard Italian itself is heavily based on the Latin-derived Florentine Tuscan language. The Tuscan-based language that would eventually become modern standard Italian had been used in poetry and literature since at least the 12th century, and it first became widely known in Italy through the works of authors such as Dante Alighieri, Giovanni Boccaccio, Niccolo Machiavelli, and Petrarch. Dante's Florentine-Tuscan literary Italian thus became the language of the literate and upper class in Italy, and it spread throughout the peninsula as the lingua franca among the Italian educated class as well as Italian traveling merchants. The economic prowess and cultural and artistic importance of Tuscany in the Late Middle Ages and the Renaissance further encouraged the diffusion of the Florentine-Tuscan Italian throughout Italy and among the educated and powerful, though local and regional languages remained the main languages of the common people.
What language is Florentine Tuscan based on?
Latin