Mark Twain three of his siblings survived childhood: Orion (1825–1897), Henry (1838–1858), and Pamela (1827–1904). His sister Margaret (1830–1839) died when Twain was three, and his brother Benjamin (1832–1842) died three years later. His brother Pleasant Hannibal (1828) died at three weeks of age. When he was four, Twain's family moved to Hannibal, Missouri, a port town on the Mississippi River that inspired the fictional town of St. Petersburg in "The Adventures of Tom Sawyer" and the "Adventures of Huckleberry Finn". Slavery was legal in Missouri at the time, and it became a theme in these writings. His father was an attorney
Mark Twain at the Territorial Enterprise the paper, which he accepted. It was during this period, on February 3, 1863, that Clemens first used his famous pen name, signing a letter complaining about a lavish party that kept him "awake for forty-eight hours" with "yours dreamily, MARK TWAIN". Twain moved to San Francisco in 1864, but in 1865 got a correspondence job with the "Territorial Enterprise" to help cope with his financial problems. From February 1865 until March 1866 when Twain left for Hawaii, he composed five or six "San Francisco Letters" to the "Enterprise". Each letter consisted of about 2,000 words and Twain was paid