Complex sentence: Sharpe was managing the project largely from Paris through a series of agents, but by the later part of 1864 the stress was adversely affecting his health, and in 1865 he spent some time in Italy to recuperate.
Split into simpler sentences: Sharpe was managing the project largely from Paris through a series of agents. By the later part of 1864 this was adversely affecting his health, and in 1865 he spent some time in Italy to recuperate.