Caractus is probably Thomas Jefferson's most well-known riding horse. Foaled on May 7, 1775, he was the offspring of Jefferson's mare Allycroker and Young Fearnought (owned by William Dandridge), a descendant of the Godolphin Arabian.
Caractacus is the Latin form of Caratacus, a 1st-century C.E. chieftain of the British Catuvellauni tribe. Caratacus led an armed resistance of the Roman invasion before finally being captured and sent to Rome as a prisoner. According to the Roman historian Tacitus, Caratacus made such a stirring speech to the Roman Senate that he was pardoned and permitted to live the rest of his life in Rome as a free man.
[no date]. "Caractacus. his sire young Feamought who was got by old Fearn. on Calista. foaled May. 1775."1
1775 May 7. "Allycroker's colt by young Fearnought was foaled May 7."2
1779 April 29. "Recd. of Lively by T. Garth for his mare put a season to Caractacus £9-19."3
[1781 May?] (Isaac Granger Jefferson's recollections of the invasion of Richmond). "When they fired the cannon Old master called out to John to fetch his horse Caractacus from the stable & rode off."4
1782 April 15. "Charge Wm. Turner a season to Caractacus."5
1782 April 23. "James Jones a season to Caractacus."6
1782 May 9. "Recd. of Jas. Jones 3/3 in full for season."7
1782 May 16. "Charge Colo. J. Harvie season of one mare to Caractacus. Recd. order on him for 45/ from Bowl. Clarke. Charge Dr. Gilmer season 3. mares."8
1782 May 24. "Charge Chas. Goodman a leap of Caractacus."9
1784 March 2. (Jefferson to John Key). "Caractacus and grey horse as he pleases. Qu. if not better for John to go with Caract. if hired."10
1790 February 22. (Jefferson to Charles Lilburne Lewis). "I send you the pedigree of Caractacus also the only two I have of the books your son desired."11