Treaty of Tolentino, in 1797 and by the Congress of Vienna in 1815. In 1825 and 1853, new attempts to submit it to the Papal States failed; and its wish to be left out of Giuseppe Garibaldi's Italian unification in the mid-nineteenth century was honoured by Giuseppe in gratitude for indiscriminately taking in refugees in years prior, many of whom were supporters of unification, including Giuseppe himself and 250 followers. Although faced with many hardships (with his wife Anita who was carrying their fifth child dying near Comacchio before they could reach the refuge), the hospitality received by Giuseppe in San Marino would later prove to be a shaping influence on Giuseppe's diplomatic manner, presaging the themes and similar language used in his political correspondences such as his letter to Joseph Cowen. 19th century In the spring of 1861, shortly before the beginning of the American Civil War, the government of San Marino wrote a letter (in "perfect Italian on one side, and imperfect but clear English on the other") to United States President Abraham Lincoln, proposing an "alliance" between the two democratic nations and offering the President honorary San Marino citizenship. Lincoln accepted the offer, writing (with his Secretary of State, William H. Seward) in reply that San Marino proved that "government founded on republican principles is capable of being so administered as to be secure and enduring." Presaging a theme he would bring to the fore, using similar language, in his Gettysburg Address in 1863, Lincoln wrote: "You have kindly adverted to the trial through which this Republic is now passing. It is one of deep import. It involves the question whether a Representative republic, extended and aggrandized so much as to be safe against foreign enemies can save itself from the dangers of domestic faction. I have faith in a good result...." After the unification of the Kingdom of Italy a treaty in 1862 confirmed San Marino's independence. It was revised in 1872. Towards the end of the 19th century, San Marino experienced economic depression: a large increase in the birth rate coupled with a widening of the gap between agricultural and industrial development led people to seek their fortunes in more industrialised countries. The Sammarinese first sought seasonal employment in Tuscany, Rome, Genoa and Trieste, but in the latter half of the century whole families were uprooted, with the first permanent migrations to the Americas (United