Phoenix Mutual Life Insurance Company of Hartford, Connecticut circular date stamp from October 1, 1898. I like the way the o and the e are segued in cancel. In the calendar below the Phoenix Company did the same with the o and e in an agent's calendar.
You can see a timeline of a history of this corporation here: http://www.phoenixwm.phl.com/public/about/history/index.jsp. This is the website for The Phoenix Companies, which remains based in Hartford, and still focuses on life insurance in 2009.