Complex sentence: Operating with two employees, they leased premises at 48 Congress Street and in May of 1881 the company was renamed Paine, Webber & Co. when Charles Hamilton Paine became a partner.
Split into simpler sentences: Operating with two employees, they leased premises at 48 Congress Street and in May of 1881. The company was renamed Paine, Webber & Co. when Charles Hamilton Paine became a partner.