1. The 1759 publication date of the Bible indicates that this record was written at least eight years after the birth of JM. In the British colonies the switch from the Julian to the Gregorian calendar was made in 1752. By the Julian calendar each year ended on 24 March rather than on 31 December. The new or Gregorian calendar also advanced the date eleven days. This change was effected by having 2 September 1752 followed immediately by 14 September 1752. The net effect of these two changes was that two periods were omitted from the chronology—3 September 1752 to 13 September 1752 and 1 January 1752 to 24 March 1752. Hence, JM was born on 5 March 1750, old style, or 16 March 1751, new style. In like manner his baptismal dates were Sunday, 20 March 1750, old style, or Sunday, 31 March 1751, new style.

2. JM was born at the home of his maternal grandmother, Mrs. John Moore (d. 1760), the former Mrs. Rebecca Catlett Conway, and of her second husband, John Moore (d. 1759). This was in King George County, opposite Port Royal, Va., on the Rappahannock River and about fifty-five miles east of the Madison plantation of Montpelier. The Reverend William Davis was rector until 1758 of the Hanover parish church which the Moores attended (Edward Lewis Goodwin, The Colonial Church in Virginia [Milwaukee, 1927], p. 263). Jonathan Gibson (d. 1791) was a large landowner in several Virginia counties. His wife, Mary Catlett Gibson, was an aunt of JM’s mother. Through the marriage of his daughter to George Taylor, Gibson was also related to JM’s father. The Misses Judith (d. 1798) and Elizabeth Catlett were also aunts of Nelly Conway Madison (Dr. and Mrs. William Carter Stubbs, comps., A History of Two Virginia Families Transplanted from County Kent, England [New Orleans, 1918], pp. 13–21; Frederick Adams Virkus, ed., The Abridged Compendium of American Genealogy [7 vols.; Chicago, 1925–42], I, 20; II, 320).