This is the grave of James Otis.
Born in West Barnstable, Massachusetts in 1725, Otis graduated from Harvard in 1743 and became a prominent lawyer in the colony. He married a wealthy woman, with strong Tory sympathies. Yet Otis himself became an important leader in the anti-British movement. He moved in this direction in 1761, when the British issued its writs of assistance, allowing British troops to enter the homes of Bostonians for any reason. It’s hard to fathom to extent to which this was a profoundly stupid policy, and while I am largely sympathetic to the British position on the American Revolution in terms of the taxes levied that at the very least were reasonable for all the trouble the American colonists caused through their love of killing indigenous people who had French allies and were consistent with contemporary British ideas of representation, British ham-handedness really undercut their position again and again.
Anyway, Otis shone in his opposition to the writs of assistance. He lost the case, but made himself a hero among contemporaries such as John Adams. He continued building on his new ideas that would influence American ideas of government through the rest of the 18th century, although he often struggled to remain consistent in them, as one can expect in someone articulating new ideas. Through the mid-1760s, he attacked the new British taxes in ways that continuing making the Patriot movement revere him. Unfortunately, Otis also suffered from mental illness going back at least to the early 1760s, which was exacerbated by a beating he took from a British tax collector in a tavern in 1769. He never really recovered from that beating and while his siblings such Mercy Otis Warren and his brothers Joseph and Samuel all played important roles in the American Revolution, James was too ill and infirm. He died in 1783, at the age of 58. Toward the end of the life, he had to deal with his wife and several of his children rejecting his political positions, with one of his daughters marrying a British officer and moving across the pond. The American Revolution was indeed the first American Civil War.
James Otis is buried in Granary Burying Ground, Boston, Massachusetts