Alexander I, czar during Napoleon's 1812 invasion of Russia, belonged to which dynasty?

Alessandro Moreschi, who died in 1922, was the last renowned singer of which type? Alexander Graham Bell's son-in-law Gilbert Grosvenor was president of which scientific society from 1920 to 1954? Alexander Hamilton, Lloyd Bentsen and George Shultz all headed which U.S. Cabinet department? Czar Alexander I entered which foreign capital in triumph in March 1814? In 1237, the Treaty of York, signed by Alexander II and Henry III, fixed a lasting border between which two kingdoms? Alexander II was called the "Czar Liberator" for freeing which Russian laborers in 1861? Alexander Khalifman, Anatoly Karpov and Garry Kasparov have all been world champions at what? Complete the title of Alexander McCall Smith's 1998 novel: "The No. 1 ___' Detective Agency".