His sister, Mehitable Stoddard Sumner, was the wife of Benjamin Welles (grandparents of philanthropist Benjamin Welles), and sister Eliza Sumner was the wife of James Watson Gerard (grandparents of diplomat James W.

[2] After graduating from college, Sumner entered the law office of district attorney John Davis, gaining admittance to the bar in 1802.

In September 1814 Massachusetts Governor Caleb Strong sent Sumner, then a lieutenant colonel in the state militia, to coordinate the defense of Portland in the District of Maine.

There were many problems with the early American militia: Some of the men were deserting and had to be brought back by force and some officers were protesting against serving under regulars.

They recommended that "a complete system of tactics and exercise for cavalry and artillery of the militia" be created.

Sumner served as its president and later on the executive committee of the company until he retired due to ill health in 1850 at age 70.

He spent many years writing the History of East Boston, a complete account of all of the early activities there, first published in 1858.

[6] When he was in Boston, Sumner resided at the family house on Mount Vernon Street in Beacon Hill.

While he retained his mental faculties to the end, he eventually succumbed to the disease and died on October 24, 1861, in Boston.