Born in Boston MA on February 16, third son of Charles Francis Adams and Abigail Brooks Adams, great-grandson of President John Adams, and grandson of President John Quincy Adams, at whose home in Quincy he was a frequent summer visitor as a boy.

Enters Harvard College. Contributes to the Harvard Magazine and is active in theatricals. Graduates as Class Orator.

Sails, September 29, with several fellow graduates, for the traditional Grand Tour of Europe. Arrives at Liverpool on October 9. Attends the university as a student of civil law in Berlin after his arrival on October 22.

Transfers to a German secondary school and writes an article on his winter’s experience there (published in American Historical Review, Oct. 1947). In April resumes study of civil law in Dresden, where he lives until April 1, 1860. During intervals tours Germany, Austria and Switzerland, and travels in northern Italy with his sister Louisa Kuhn.

Travels in Italy and Sicily from April until June. Interviews the Italian patriot Garibaldi just after the surrender of the Bourbon troops. Publishes his Italian travel letters in the Boston Daily Courier. After a ten-week stay in Paris he returns to Quincy MA in October. In December acccompanies his father who had been re-elected to Congress to Washington as his private secretary. December to mid March 1861, serves as Washington correspondent of the Boston Daily Advertiser. Prepares "The Great Secession Winter, 1860-1861" (published in Proceedings, Massachusetts Historical Society, 1909-10)

Sails for England, May 1. Serves as private secretary to his father, whom Lincoln has appointed as minister to Great Britain, until his father’s resignation in May 1868. As London correspondent of The New York Times from June 1861 to January 1862, Adams reports British reaction to the American Civil War. His father sends Adams as a special messenger to the King of Denmark, December 1862. Tours Scotland and the Isle of Skye in August 1863 with his fifteen-year-old brother Brooks.

Grows restless with London society. Travels with mother, sister, and younger brother in Italy from December 1864 till June 1865. Returns to London; but pays several visits to the Continent.

Publishes "Captaine John Smith" in the North American Review, demonstrating that that idol of Virginians had invented the tale of his rescue by Pocahontas. Also publishes "British Finance in 1816" and "The Bank of England Restriction," the latter illustrating the futility of issuing inconvertible paper money.

Publishes a long review article on Sir Charles Lyell’s tenth edition of his Principles of Geology in the North American Review, challenging current theories of glaciation and Darwin’s theory of evolution as "in its nature incapable of proof." Returns to America in July with his parents and begins work in Washinton as a free-lance political journalist and lobbyist in favor of currency reform, free trade, and the establishment of civil service, contributing occasional pieces to the New York Nation toward the end of the year.

Attacks the subservience of Congress to special interests and its reliance on the spoils system in "The Session" and "Civil Service Reform," articles published in the North American Review. Publishes "American Finance, 1865-1869," an article critical of the financial expedients of the period, in the Edinburgh Review. Continues brief contributions to the Nation into 1870.

Publishes "The Legal Tender Act" (with the assistance of Francis A. Walker), vigorously attacking that legislation and its sponsor Elbridge G. Spaulding, and a second "Session" critical of Congress in the North American Review. Adams makes a holiday visit to England, but he is shortly summoned to his sister Louisa’s bedside at Bagni di Lucca, where on July 13 she dies of tetanus, leaving Adams with a lasting impression of Nature’s indifference to human suffering. Is appointed assistant professor of history by Charles W. Eliot, the new president of Harvard College. Begins teaching courses in medieval English and European history; later adds courses in American history. Assumes editorship of the North American Review, to which he contributes two articles and over twenty reviews over the next seven years. Finally places his sensational exposé, "The New York Gold Conspiracy," in the Westminster Review. Drops the use of his middle name, Brooks.

Publishes with his brother Charles Francis Adams, Jr., Chapters of Erie, a collection of some of their previously published articles. Travels to the Far West where he meets Clarence King of the United States Geological Survey. King soon afterward brings him into the circle of scientists connected with the Survey and the Smithsonian Institution.

On June 27, Adams marries Marian (Clover) Hooper, daughter of the retired physician Dr. Robert William Hooper, a prominent Bostonian and a long-time widower. They sail July 9 on a wedding journey to England, the Continent, and Egypt. Adams renews friendships with Sir Robert Cunliffe, Charles Milnes Gaskell, Francis Palgrave, and Thomas Woolner, and consults European and English Scholars such as Heinrich von Sybel, Ernst Curtius, Heinrich von Gneist, Georg H. Pertz, Theodor Mommsen, William Stubbs, John Richard Green, Sir Henry Maine, Robert Laing, and Benjamin Jowett. Returns to Boston August 1873.

Publishes Essays in Anglo-Saxon Law, which includes his own essay "Anglo-Saxon Courts of Law" and three essays written by his doctoral candidates—Henry Cabot Lodge, Ernest Young, and James Lawrence Laughlin. Publishes "The Independents in the Canvass" in the North American Review, urging Republicans to break away from the conservative regular party. The article offends the publisher and leads to Adams’s ending his connection with the Review. In December Adams delivers his Lowell Institute lecture, "Primitive Rights of Women."

Resigns from Harvard after accepting an invitation to work on the papers of Albert Gallatin, Thomas Jefferson’s Secretay of the Treasury. As a friend of Secretary of State Evarts, Adams is given full access to the State Department archives. Publishes Documents Relating to New England Federalism in defense of the anti-Federalist policy of John Quincy Adams.

Publishes The Life of Albert Gallatin and The Writings of Albert Gallatin. Forms friendships with Senator James D. Cameron and his wife, Elizabeth, and with John Hay, former private secretary of Abraham Lincoln. An inner circle of intimate friends is stablished of "The Five of Hearts"—the Adamses, John and Clara Hay, and Clarence King. Adams’s wife presides over exclusive salon, which attracts friends such as Secretary of the Interior Carl Schurz, Attorney General Charles Devens, Senator Lucius Lamar of Mississippi, Congressman Abram Hewitt, Turkish minister Aristarchi Bey, and a procession of diplomats and foreign visitors. Adams begins acquaintance with a long succession of American presidents.

Travels in Europe researching archives of London, Paris, and Madrid for his projected history of the administrations of Jefferson aud Madison.

Anonymously publishes Democracy: An American Novel, widely read in the United States and England for its depiction of political corruption in Washington.

Under the pseudonym Frances Snow Compton publishes Esther: A Novel. Adams and Hay begin construction of their residences on H Street facing Lafayette Square in Washington. The houses were designed by Adams’s college mate, Henry Hobson Richardson. Circulates six copies, privately printed, of the first section of his History of the United States during the Administrations of Thomas Jefferson and James Madison to a few intimates for criticism.

Circulates six copies of the second section of the history. Dr. Hooper, Adams’s father-in-law, dies in April. On December 6, Adams’s wife, Marian, commits suicide. Shortly afterward moves into the just-completed house at 1603 H Street.

Commissions bronze figure to be executed by American sculptor Augustus Saint-Gaudens for the gravesite of Marian Adams in Rock Creek Cemetery. June to October, Adams tours Japan with artist John La Farge. November 21, Adams’s father dies at Quincy at age seventy-nine.

Circulates six copies of the third section of the History. (The fourth section was set directly from manuscript.) Adams makes his frirst trip to Cuba. Makes a circle tour of the Far West with his English friend Robert Cunliffe.

Charles Scribner’s Sons publishes the first two volumes of the trade edition of the History (four more volumes are published in 1890; the final three volumes and the volume of Historical Essays are published in 1891). June 6, Adams’s mother dies at Quincy at age eighty-one. Adams becomes increasingly dependent on his friendship with Elizabeth Cameron.

Adams travels with John La Farge to Hawaii, Samoa, Tahiti, Fiji, Australia, and Ceylon from August 1890 to September 1891. Writes poem "Buddha and Brahma" aboard ship en route from Ceylon (published in The YaIe Law Review, Oct. 1915). Has a reunion with Elizabeth Cameron in France. Leaves England for America February 3, 1892.

Recalled from Europe as the family fortunes suffer in the Panic of that summer, he commences intellectual collaboration with his brother Brooks, whose radical Law of Civilization and Decay will appear in 1895. Privately prints Memoirs of Marau Taaroa, Last Queen of Tahiti. Twice visits the World Columbian Exposition in Chicago, whose buildings seem to him to promise a renaissance in art and architecture.

In December, sends his presidential address predicting the development of scientific history to the annual meeting of the American Historical Association to be delivered in absentia ("The Tendency of History," published in Annual Report of the American Historical Association for the Year 1894). Tours Cuba with Clarence King, February to March; travels to the Yellowstone and the Tetons with John Hay, July to September; tours Mexico and the Caribbean Islands with Chandler Hale, December 1894 to April 1895.

Adams makes his first systematic study of the Gothic architecture of Normandy cathedrals and Mont Saint Michel in the company of Henry and Anna Cabot Lodge.

Prepares "Recognition of Cuban Independence" for Senator Cameron, printed in the Senate Report. In April, travels to Mexico with the Camerons. Tours Europe with the Hays, May to October.

Prolonged stay abroad is spent in London, Paris, Egypt (with the Hays), Turkey, Greece, the Balkans, Vienna, and Paris. Is in England June to November. While visiting with Adams at Surrenden Dering in England, Hay is appointed U.S. Secretary of State, having served as ambassador to England since March 1897.

Tours Italy and Sicily with the Lodges. Resides in Paris, June to January 1900. (Until 1911, in Paris for part of each year; from 1908 as member of Edith Wharton’s circle.)

Visits the Paris Exposition and is especially impressed by the Hall of Dynamos. Composes the poem "Prayer to the Virgin of Chartres," which includes a "Prayer to the Dynamo" (published 1920, in Mabel La Farge, Letters to a Niece).

Revises and enlarges the Tahiti memoir as Memoirs of Arii Taimai for private distribution. Travels with the Lodges during July and August to Bayreuth, Vienna, Warsaw, Moscow, and St. Petersburg, then alone during September to Sweden and Norway.

Privately prints Mont Saint Michel and Chartres. Contributes chapter on Clarence King in Clarence King Memoirs. In the spring, accompanies Secretary of State John Hay to the opening of the St. Louis Exposition.

In February, issues the private edition of The Education of Henry Adams, containing the first formulation of his Dynamic Theory of History and his Law of Acceleration. Circulates the volume for correction to persons it comments on, including his brothers, Henry Cabot Lodge, Charles Gaskell, Theodore Roosevelt, Charles William Eliot, and Speck von Sternburg.

Edits the Letters of John Hay and Extracts from Diary, but Adams surrenders completion to Hay’s widow, who reduces the names to initials.

Writes "The Rule of Phase Applied to History," in which he reformulates his theory of scientific history, now basing it on an analogy to Josiah Willard Gibbs’s "Rule of Phase" contained in Gibbs’s "On the Equilibrium of Heterogeneous Substances."

Prints and distributes to university libraries and history professors the small volume A Letter to American Teaches of History proposing a theory of history based on the Second Law of Thermodynamics and the principle of entropy.

Publishes The Life of George Cabot Lodge, prepared at the instance of the Lodges.

Issues a second private edition, slighty revised, of Mont Saint Michel and Chartres. Is partially paralyzed by a cerebral thrombosis, April to late July.

Authorizes the American Institute of Architects to publish a trade edition of the Chartres, edited by Ralph Adams Cram and issued through Houghton Mifflin Company. The advance sale breaks the publisher’s records.

Spends summers again in France, first at the Chateau Marivault in the countryside north of Paris and subsequently at the Chateau Coubertin. Engages Aileen Tone, a musician as secretary-companion and becomes engrossed in the study and performance of medieval chansons.

Presides at his noontime breakfast table at 1603 H Street during the War years entertaining nieces and "nieces in wish" and visiting dignitaries such as Arthur Balfour, Henri Bergson, and French Ambassador Jusserand.

Dies in Washington March 27 at thc age of eighty. Buried beside his wife in Rock Creek Cemetery. First trade publication of The Education of Henry Adams. "Tendency of History," "Rule of Phase Applied to History," and "A Letter to American Teachers" are included by Brooks Adams in The Degradation of the Democratic Dogma (1919). The Pulitzer Prize is awarded posthumously in 1919 for The Education.