Arabella Maria Smith (known as Maria) was born in Devonshire England, the daughter of Major George Smith of the British Army, who was stationed in the Caribbean. She met and married Alexander James Dallas in 1780 when she was only 16, and soon moved to Jamaica, where Mr. Dallas practiced law. However, the tropical climate was difficult for her health, and they moved to Philadelphia, PA in 1783 where they became U.S. citizens. Alexander Dallas wrote for local publications including the Pennsylvania Evening Herald, and he edited the Columbia Magazine. By 1785, he had been admitted to the Pennsylvania Supreme Court bar. The Dallases formed many influential friendships with state and civic leaders, including Aaron Burr and Albert Gallatin. Dallas became Secretary of the Commonwealth of Pennsylvania in 1791 and held the post for 10 years. Starting in 1794 he also served as the paymaster and aide-de-camp for Governor Thomas Mifflin during the whiskey rebellion. He may have met George Washington at this time, and he corresponded with him several times. Dallas became US attorney for eastern Pennsylvania in 1801, a post he held until becoming Secretary of the Treasury in 1814.