A.M. = Anno Mundi; that is to say, in the year of the world.
B.C. = Before Christ. Reckoned as from 4004 A.M.
A.C. = Anno Christi; that is to say, in the year of Christ. Reckoned from the Nativity, in 4000 A.M. and 749-750 A.U.C.
A.U.C. = Anno Urbis Conditoe; that is to say; the year in which the City (Rome) was founded.

A.M.	B.C. - A.D.	A.C.	A.U.C.	YEARS OF THE REIGN OF AUGUSTUS (OCTAVIUS).	YEARS OF THE REIGN OF TIBERIUS.
3960	44		9
1	43		710
2	42		11
3	41		12
4	40		13
5	39		14   Herod declared king by the Romans, according to Josephus (Ant.xvii. 8 § 1), who states that his death took place thiryt-seven years later, and as he always reckoned his years from Nisan to Nisan (including initial and terminal fractions of Nisan as complete years), the death of Herod would be in 749-750 A.U.C., or 4-3 B.C.
6	38		15
7	37		16
8	36		17
9	35		18
3970	34		19
1	33		720
2	32		21
3	Battle of Actium   31		722	1st    year of Octavius.
4	30   Decree of Senate of Rome.		23	2
5	29		24	3
6	28		25	4
7	27		26	5   AUGUSTUS (Octavius) IMPERATOR
8	26		27	6
9	25		28	7
3980	24		29	8
1	23		730	9
2	22		31	10
3	21		32	11
4	20		33	12
5	19		34	13
6	18		35	14
7	17		36	15
8	16		37	16
9	15		38	17
3990	14		39	18
1	13		740	19
2	12		41	20
3	11		42	21
4	10		43	22
5	9		44	23
6	8		45	24
7	7		46	25
8	6		47	26
9	{5}		48	27
(See Appendix 50)   4000	THE NATIVITY 1st taxing or Census Luke 2:2 {4	YEARS OF THE  AGE OF THE LORD 0}	749 Herod d.c end of January 3 B.C.	28 Our Lord birth 15th Tisri = 29th September 4 B.C.
{1	{3	Quirinus' First Governorship.  1}	750	29
{2	{2	2}	51	30
3	{1	3}	52	31
4004	0  A.D.	4	753	32  A.D. reckoning begins, owing to the mistake of Dionysius Exiguus in arranging the Calendar of the Christian Era in A.D. 532.
5	1	5	54	33
6	2	6	55	34
7	3	7	56	35
8	4	8	57	36
9	5	9	58	37
4010	6	10	59	38
1	7	11	760	39
2	8	12  Christ in the Temple	61	40
3	9	13	62	41
4	2nd Census (?) 10	14	63	42	YEARS OF THE REIGN OF TIBERIUS.
5	11	15	64	43
6	12	16	65	44  1st yr. of Tiberius'	1  joint reign with Augustus.
7	13	17	66	45	2
8	14	18	67	19th August   46 Augustus dies.	3 Tiberius alone.
9	15	19	68		4
4020	16	20	69		5
1	17	21	770		6
2	18	22	71		7
3	19	23	72		8
4	20	24	73		9
5	21	25	74		10
6	22	26	75		11
7	23	27	76		12
8	3rd Census (?)  24	28	77		13  3rd Census this year (?).
9	25	29	78		14
4030	26 The Ministry	30 of our	779 Lord	begins (Luke 3:23) in the	15th year of Tiberius.
1	27	31	780		16
2	28	32	81		17
ANNO MUNDI 4033	THE CRUCIFIXION 29	A.D.THE LORD 33	YEARS OF AGE.	A.U.C. ROMAN RECKONING. 782	THE 18th year of Tiberius.

1. ZUMPT fixes Quirinus' (Cyrenius') First Govenorship as 4 B.C. to 1 B.C.  Justin Martyr thrice says that our Lord was born under Quirinus (Apol.1.XXXIV, p.37; XLVI, p. 46; Dial. LXXVIII, p. 195. Clark's ed.).
   
   
2. According to some, Augustus died August 19, A.D. 14.  Therefore if Tiberius' co-regnancy was for two years before Augustus' death his first year was 765 A.U.C. = 12 A.D.  His fifteenth year consequently was A.U.C. 779 = 26 A.D. = 4030 A.M. and A.C. 30.  for our Lord was thirty years of age when He begun His Ministry (Luke 3:23).  Clement of Alexandria gives the years of Augustus' reign as being 43-46, according to different reckonings in his day.
   
   
3. According to Clement of Alexandria (c. A.D. 190-220) "Our Lord was born in the twenty-eighth year when first the census was taken every fourteen years, then the next would fall in A.D. 10, and the succeeding one would have been due A.D.24.
    

1. It thus appears without the shadow of a doubt that the day assigned the the Birth of the Lord, viz. December 25, was the day on which He was "begotten of the Holy Ghost", i.e. by pneuma hagion = divine power (Matt. 1:18, 20 marg.), and His birth took place on the 15th of Ethanim, September 29, in the year following, thus making beautifully clear the meaning of John 1:14, "The Word became flesh" (Matt. 1:18, 20) on the 1st Tebeth or December 25 (5 B.C.), "and tabernacled (Gr. eskeno-sen) with us", on 15th of Ethanim or September 29 (4 B.C.).
   
   The 15th of Ethanim (or Tisri) was the first day of the Feast of Tabernacles.  The circumcision therefore took place on the eighth day of the Feast = 22nd Ethanim = October 6-7 (Lev. 23:33-34).  So that these two momentous events fall into their proper place and order, and the real reason is made clear why the 25th of December is associated with our Lord and was set apart by the Apostolic Church to commemorate the stupendous event of the "Word becoming flesh" - and not, as we have for so long been led to suppose, the commemoration of a pagan festival.
   
   
2. An overwhelmingly strong argument in favor of the correctness of this view lies in the fact that the date of "the Festival of Michael and All Angels" has been from very early times the 29th day of September, on Gentile (Western) reckoning.  But "the Church" even then had lost sight of the reason why this date rather than any other in the Calendar should be so indissolubly associated with the great Angelic Festival.
   
   
3. The following expresses the almost universal knowledge or rather want of knowledge of "Christendom" on the subject:  "We pass on now to consider, in the third place, the commemoration of September 29, the festival of Michaelmas, par excellence.  It does not appear at all certain what was the original special idea of the commemoration of this day"  (Smith's Dict. of Chr. Antiqq. (1893), vol. ii, p. 1177 (3) ).
   
   A reference, however, to the Table and statements above, makes the "original special idea " why the Festival of  "Michael and All Angels" is held on September 29 abundantly clear.  Our Lord was born on that day, the first day of the "Feast of Tabernacles" (Lev. 23:39).  This was on the fifteenth day of the seventh Jewish month called Tisri, or Ethanim (Ap. 51. 5), corresponding to our September 29 (of the year 4 B.C.) The "Begetting" (gennesis) Day of the Lord was announced by the Angel Gabriel.  See notes on Dan. 8:16 and Luke 1:19. The "Birth" Day, by "(the) Angel of the Lord", unnamed in either Matthew and Luke.
   
   That this Angelic Being was "Michael the Archangel (of Jude 9), and Mika'el hassar haggadol - "Michael the Great Prince"- of Dan. 12:1, seems clear for the following reason:  If, "when again (yet future)  He bringeth the First-begotten into the world, He saith, Let all the Angels of God worship Him" (Heb 1:6; quoting  Ps. 97:6) - then this must include the great Archangel Michael himself.  By parity of reasoning, on the First "bringing" into the world of the only begotten Son, the Archangel must have been present.  And the tremendous announcement to the shepherds, that the Prince of Peace (Isa. 9:6) was on earth in the person of the Babe of Bethlehem, must therefore have been made by the same head of the heavenly host (Luke 2:9-14).  In mundane affairs, announcements of supremest importance (of kings, &c.) are invariably conveyed through the most exalted personage in the realm.  The point need not be labored.
   
   
4. The fact of the Birth of our Lord having been revealed to the shepherds by the Archangel Michael on the 15th of Tisri (or Ethanim), corresponding to September 29, 4 B.C.  - the first day of the Feast of Tabernacles - must have been known to believers in the Apostolic Age.  But "the mystery of iniquity" which was "already working" in Paul's day (2Thess. 2:7) quickly enshrouded this and the other great fact of the day of the Lord's "begetting" on the first day of the Jewish month Tebeth (corresponding to December 25, 5 B.C.) - as well as other events connected with His sojourn on earth, (*1) - in a rising mist of obscurity in which they have ever since been lost.
   
   The earliest allusion to December 25 (modern reckoning) as the date for the Nativity is found in the Stromata of Clement of Alexandria, about the beginning of the third century A.D. (See note 3 p. 197). (*2)
   
   That "Christmas" was a pagan festival long before the time of our Lord is beyond doubt.  In Egypt Horus (or Harpocrates (*3), the son of Isis (Queen of Heaven), was born about the time of winter solstice. (*4)  By the time of the early part of the fourth century A.D., the real reason for observing Christmas as the date for the miraculous "begetting" of Matt. 1:18 and "the Word becoming flesh" of John 1:14 had been lost sight of.  The policy of Constantine, and his Edict of Milan, by establishing universal freedom of religion furthered this.  When many of the followers of the old pagan systems - the vast majority of the empire, it must be remembered - adopted the Christian religion as a cult, which Constantine had made fashionable, and the "Church" became the Church of the Roman Empire, they brought in with them, among a number of other things emanating from Egypt and Babylon, the various Festival Days of the old "religions".  Thus "Christmas Day, " the birthday of the Egyptian Horus (Osiris), became gradually substituted for the real Natalis Domini of our blessed Savior, viz. September 29, or Michaelmas Day.
   
   
5. If however, we realize that the center of gravity, so to speak, of what we call the Incarnation if the Incarnation itself- the wondrous fact of the Divine "begetting", when "the Word became flesh" (see notes on Matt. 1:18 and John 1:14) - and that this is to be associated with December 25, instead of March - as for 1,600 years Christendom has been led to believe - then, "Christmas" will be seen in quite another light, and many who have hitherto been troubled with scruples concerning the day being, as they have been taught, the anniversary of a Pagan festival, will be enabled to worship on that Day without alloy of doubt, as the time when the stupendous miracle which is the foundation stone of the Christian faith, came to pass.
   
   The "Annunciation" by the Angel Gabriel marked the gennesis of Matt. 1:18, and the first words of John 1:14.  The announcement to the shepherds by the Archangel Michael marked the Birth of our Lord.  John 1:14 is read as though "the Word became flesh (R.V.) and dwelt among us ", were one and the same thing, whereas they are two clauses.

   The paragraph should read thus:

   "And the Word became flesh; (Gr. ho logos sarz egeneto.)
   And tabernacled with (or among) us." (Gr. kai eskenosen en hemin).

   The word tabernacled here (preserved in R.V. marg.) receives beautiful significance from the knowledge that "the Lord of glory" was "found in fashion as a man", and thus tabernacling in human flesh.  And in turn it shows in equally beautiful significance that our Lord was born on the first day of the great Jewish Feast of Tabernacles, viz. the 15th of Tisri, corresponding to September 29, 4 B.C. (modern reckoning).  The Circumcision of our Lord took place therefore on the eighth day, the last day of the Feast, the "Great Day of the Feast" of John 7.37 ("Tabernacles" had eight days.  The Feast of Unleavened Bread had seven days and Pentecost one.  See Lev. 23)
   
   
6. The main arguments against the Nativity having taken place in December may be set forth very simply:
   
   
   1. The extreme improbability, amounting almost to impossibility, that Mary, under such circumstances, could have undertaken a journey of about 70 miles (as the crow flies), through a hill district averaging some 3,000 feet above sea-level, in the depth of winter:
      
      
   2. Shepherds and their flocks would not be found "abiding" (Gr. agrauleo) in the open fields at night in December (Tebeth), for the paramount reason that there would be no pasturage at that time.  It was the custom then (as now) to withdraw the flocks during the month Marchesvan (Oct.-Nov.) (**1) from the open districts and house them for the winter.
      
      
   3. The Roman authorities in imposing such a "census taking" for the hated and unpopular "foreign" tax would not have enforced the imperial decree (Luke 2:1) at the most inconvenient and inclement season of the year, by compelling the people to enroll themselves at their respective "cities" in December.  In such a case they would naturally choose the "line" of least resistance" and select a time of year that would cause least friction, and interference with the habits and pursuits of the Jewish people.  This would be in the autumn, when the agricultural round of the year was complete, and the people generally more or less at liberty to take advantage, as we know many did, of the opportunity of "going up" to Jerusalem for the "Feast of Tabernacles" (cp. John 7:8-10, &c), the crowning Feast of the Jewish year.
   
   To take advantage of such a time would be to the Romans the simplest and most natural policy, whereas to attempt to enforce the Edict of Registration for the purpose of Imperial taxation in the depth of winter,- when traveling for such a purpose would have been deeply resented, and perhaps have brought about a revolt,- would never have been attempted by such an astute ruler as Augustus.
7. With regard to the other two "Quarter Days", June 24, March 25, these are both associated with the miraculous (Luke 1:7) "conception" and birth of the Forerunner, as December 25 and September 29 are with our Lord's miraculous "Begetting" and Birth; and are therefore connected with "the Course of Abiah."

(**1) It is true that the Lebanon shepherds are in the habit of keeping their flocks alive during the winter months, by cutting down branches of trees in the forests in that district, to feed the sheep on the leaves and twigs, when in autumn the pastures are dried up, and in winter, when snow covers the ground.  (cp. Land and Book, p.204), but there is no evidence that the Bethlehem district was afforested in this manner.

The first (*1) ministration was from 12 - 18 Chisleu = December 6 - 12.
The second ministration was from 12 -18 Sivan = June 13 - 19.

The day following the end of the "Course of Abia" being a Sabbath (Sivan 19), he would not be able to leave Jerusalem before the 20th.  The thirty miles journey would probably occupy, for an old man, a couple of days at least.  He would therefore arrive at his house on the 21st or 22nd.  This leaves ample time for the miraculous "conception" of Elizabeth to take place on or about the 23rd of Sivan (*3) - which would correspond to June 23 -24 of that year.  The fact of the conception and it's date would necessarily be known at the time and afterwards, and hence the 23rd of SIVAN would henceforth be associated with the conception of John the Baptist as the 1st of TEBETH would be with that of our Lord.

But the same influences that speedily obscured and presently obliterated the real dates of our Lord's "Begetting" and Birth, were also at work with regard to those of the Forerunner, and with the same results.  As soon as the true Birth day of Christ had been shifted from its proper date, viz. the 15th of Tisri (September 29), and a Festival Day from the Pagan Calendars substituted for it (viz. December 25), then everything else had to be altered too.

Hence "Lady Day" in association with March 25 (new style) became necessarily connected with the Annunciation.  And June 24 made its appearance as it still is in our Calendar, as the date of  "the Nativity of John the Baptist", instead of , as it really is, the date of his miraculous conception.
The Four "Quarter Days" may therefore be set forth thus: first in the chronological order of the events with which they are associated, viz.:   

or, placing the two sets together naturally : --