John Hartwell Cocke was a Virginia planter and amateur architect whose style evolved from Jeffersonian Classicism to a revival of English Tudor-Stuart or Jacobethan architecture. This dissertation discusses the Cocke family's Elizabethan roots and advances four theses. The first of these theses is that John Hartwell Cocke implemented Thomas Jefferson's principles for the reform of Virginia architecture. Cocke's most ambitious project, a Jeffersonian Palladian mansion called Bremo, was in the planning stages by 1815. The second thesis is that Cocke's off-plantation buildings signals his break from the Palladianism of Thomas Jefferson in favor of the Jacobean style for his houses and his acceptance of classical Jeffersonian elements for public buildings. The third thesis proposes John Hartwell Cocke as the first practitioner of the Romantic Colonial Revival movement in America in his revival of Tudor-Stuart architecture. The fourth thesis is that John Hartwell Cocke's architectural legacy was expanded by Philip St. George Cocke, the second of his three sons, when the younger Cocke commissioned Alexander J. Davis to build Belmead and later promoted Davis among his circle of family and friends.