The Book of Mormon contains a chronology that is internally consistent over the thousand-year Nephite history, with precise Nephite dates for several events, including the crucifixion of Jesus Christ. However, its chronology has not been unequivocally tied to other calendars because of uncertainties in biblical dates and lack of details about the Nephite calendars. Even less information exists about Jaredite chronology (Sorenson, 1969).
Internal Nephite Chronology. Nephites kept careful track of time from at least three reference points:
The Book of Mormon links all three systems in several passages that are apparently consistent. Table 1 lists several events using the Nephite systems.
Most of the Nephite record pertains to three historical periods: the time of Lehi and his sons (c. 600—500 B.C.), the events preceding and following the coming of Christ (c. 150 B.C.—A.D. 34), and the destruction of the Nephites (c. A.D. 300—420). Thus, the relatively large book of Alma covers only thirty-nine years, while the much smaller books of Omni and 4 Nephi each cover more than two hundred years.
LDS editions of the Book of Mormon show dates in Nephite years, deduced from the text, at the bottom of the pages. The exact nature of the Nephite year, however, is not described. The Nephite year began with the "first day" of the "first month" (Alma 51:37—52:1; 56:1), and it probably had twelve months because the eleventh month was at "the latter end" of the year (Alma 48:2, 21; 49:1), but the lengths of the months and of the year itself are not mentioned.
Until the coming of Christ, the Nephites observed the Law of Moses (2 Ne. 25:24; Alma 25:15), which generally used lunar months (new moon to new moon). The Savior was crucified on the fourteenth day of the first lunar month of the Jewish calendar (John 19:14; Lev. 23:5), but on the fourth day of the first Nephite month (3 Ne. 8:5). This may imply that Nephite months at that time were not lunar and that their civil calendar may have differed from their religious calendar.
John L. Sorenson (1990) has observed that during the reign of the judges warfare was mostly limited to four consecutive Nephite months. These months can be approximately correlated with our calendar because even today warfare in Mesoamerica (the probable area of Book of Mormon geography for most of Nephite history) is conducted mostly during the dry season after the fall harvest. This correlation implies that the Nephite year at that time began in December (see warfare in the book of Mormon). This would mean that because the crucifixion of Christ (presumably in early April) occurred in the first Nephite month, the Nephites probably shifted their calendar to begin the first month in April at the same time they began reckoning time from the birth of Christ. This conclusion is consistent with the Nephite record that Christ was born some time after the end of the Nephite year (3 Ne. 1:1—9).
External Chronology. Evidence supports two possible lengths for Nephite years: 365 days and 360 days. Each can be correlated to external history. The internal chronology is consistent, so that if the exact nature of the Nephite calendar were known, only one reference point in external history would be needed to fix the entire Nephite chronology. However, at least two such dates would be required to determine the length of the Nephite year. Three principal events are common to both Nephite and Old World sources: (1) the first year of the reign of Zedekiah, King of Judah; (2) the birth of Christ; and (3) the death of Christ. Because there are varying degrees of uncertainty about these three reference points, alternative correlation methods have been proposed, each using two of these dates.
First, Orson Pratt proposed that the Nephites used a 365-day year, as had the Egyptians previously and as did the Mesoamericans afterward (Millennial Star 28 [Dec. 22, 1866]: 810). It has been noted (Lefgren) that such a year agrees, to the very day, with one choice for the birth and death dates of Christ—namely, Thursday, April 6, 1 B.C., and Friday, April 1, A.D. 33, respectively (Gregorian calendar). Both of these dates are supported by other arguments (J. Pratt, 1985 and 1990). This theory assumes that the third system of Nephite reckoning began on the very day of the birth of Christ, which is not explicitly stated in the Book of Mormon but is consistent with Sorenson's conclusions above.
Second, most historians believe that the first year of King Zedekiah began in 598—596 B.C. Lehi left Jerusalem shortly afterward (1 Ne. 1:4; 2:4). The date of the birth of Christ is not known directly from historical sources, but it is believed that King Herod died in 5—4 B.C., implying that Christ was born shortly before (Matt. 2:1). Using these two events as reference points, Huber has proposed a 360-day Nephite year because 600 such years fit the interval from Lehi to Christ (3 Ne. 1:1); such a system has historical precedent, and apparently underlies certain prophecies in which the word "time" may equal 360 days (e.g., Rev. 12:6, 14).
Brown, S. Kent; C. Wilfred Griggs; and H. Kimball Hansen. "Review of April Sixth by John C. Lefgren." BYU Studies 22 (Summer 1982): 375—83. See rebuttal and response in BYU Studies 23 (Spring 1983): 252—55.
Huber, Jay H. "Lehi's 600 Year Prophecy and the Birth of Christ." FARMS Paper. Provo, Utah, 1982.
Lefgren, John C. April Sixth. Salt Lake City, 1980.
Pratt, John P. "The Restoration of Priesthood Keys on Easter 1836. Part 1: Dating the First Easter." Ensign 15 (June 1985): 59—68.
———. "Yet Another Eclipse for Herod." The Planetarian 19 (Dec. 1990): 8—14.
Sorenson, John L. "The Years of the Jaredites." FARMS Paper. Provo, Utah, 1969.
———. "Seasonality of Warfare in the Book of Mormon and in Mesoamerica." In Warfare in the Book of Mormon, ed. S. Ricks and W. Hamblin, pp. 445—77. Salt Lake City, 1990.
John P. Pratt