Complex sentence: Mary Margaret O'Reilly (October 14,1865--December 6,1949) was the Assistant Director of the United States Bureau of the Mint for 34 years, from 1904 to her retirement in 1938.
Split into simpler sentences: Mary Margaret O'Reilly (October 14,1865--December 6,1949) was the Assistant Director of the United States Bureau of the Mint. She worked at the Mint for 34 years, from 1904 to her retirement in 1938.