Complex sentence: A. Oakley Hall (1826--1898) was Mayor of New York City from 1869-1872, was alleged to be part of the vilified "Tweed Ring" which started as a lunch group between some of Mayor Van Buren's administration and immigrant political organizers.
Split into simpler sentences: A. Oakley Hall (1826--1898) was Mayor of New York City from 1869-1872. He was alleged to be part of the vilified "Tweed Ring" which started as a lunch group between some of Mayor Van Buren's administration and immigrant political organizers.