John Marshall Brown (1838-1907) of Portland met Alida Carroll (1844-1911) of Washington D.C. while he was serving as a general in the Civil War. The couple married in 1866, living in Portland and at Thornhurst, their farm on Falmouth Foreside.

The Browns are the namesakes of MHS's Alida Carroll and John Marshall Brown Research library. Maine Historical Society (MHS) re-dedicated the building to the Browns in 2009 after a restoration and expansion project, recognizing their commitment to Maine history.

John Marshall Brown first engaged with MHS while he was studying at Bowdoin College, graduating in the class of 1860. An active member, he spearheaded MHS’s physical move back to Portland and supported the publication of MHS’s Documentary History of the State of Maine (1869-1916). Alida Carroll Brown was active in Maine chapters of the Colonial Dames and Daughters of the American Revolution.

Brown worked for the family’s real-estate firm, J.B. Brown & Sons, which once owned MHS's museum building—hence the name Brown Street. His father, John Bundy Brown found initial success in the dry goods business, specifically the Portland Sugar Company. Maine ships brought molasses, farmed through slave labor in Cuba, into Portland. Resources from this successful business helped support the Brown's future ventures, including the Maine Historical Society.