EASTER.
Easter (Germ. _Ostern_, Old Saxon _Oster_, from _Osten_, signifying
rising). The English name is probably derived from Ostera or Eostre, the
Teutonic goddess of spring, whose festival occurred about the same time of
the year as the celebration of Easter. The Hebrew-Greek word Pascha has
passed into the name given to this feast by most Christian nations. This
festival is held in commemoration of our Lord's resurrection.
The Jews celebrated their passover, in conformity with the directions
given them by Moses, on the 14th day of the month Nisan, being the lunar
month of which the 14th day either falls on or next follows the day of the
vernal equinox. In the year of our Lord's crucifixion this fell on a
Friday; the resurrection, therefore, took place on the first day of the
week, which from thence is denominated the Lord's Day.
The primitive Christians, in celebrating this anniversary, fell into two
different systems. The Western churches observed the nearest Sunday to the
full moon of Nisan, taking no account of the day on which the passover
would be celebrated. The Asiatics, on the other hand, following the Jewish
calendar, adopted the 14th of Nisan upon which to commemorate the
crucifixion, and observed the festival of Easter on the third day
following, upon whatever day of the week that might fall, hence they
obtained the name of Quartodecimans, (from quarto, four, and decem, ten,)
the fourteenth day men. The former appealed to the authority of St. Peter
and St. Paul, the latter to that of St. John.
The dispute which took place upon this point in the second and third
centuries of our era is remarkable, as connected with perhaps the first
event which can be brought to bear upon the question of the primacy of the
Roman bishop; and it is the more interesting as both parties are
accustomed to claim it as a testimony in favor of their own views. Victor,
bishop of Rome, wrote an imperious letter to the Asiatic bishops,
requiring their conformity to the Western rule; which was answered by
Polycrates, bishop of Ephesus, in the name of the rest, expressing their
resolution to maintain the custom handed down to them by their ancestors.
The Roman bishop thereupon broke off communion with them; but he was
rebuked by Irenaeus, of Lyons, and it was agreed by his mediation that
each party should retain its customs. Such continued to be the practice
till the time of Constantine, when the Council of Nice determined the
matter by the following Canons:
_a_--Easter must be celebrated on a Sunday.
_b_--This Sunday must follow the 14th day of the paschal moon, so that if
the 14th day of the paschal moon fall on a Sunday, then Easter must be
celebrated on the Sunday following.
_c_--The paschal moon is that moon of which the 14th day either falls on
or next follows the day of the vernal equinox.
_d_--The 21st of March is to be accounted the day of the vernal equinox.
(Appendix L.)
Sometimes a misunderstanding has arisen from not observing that this
regulation is to be construed according to the tabular full moon as
determined from the epact, and not by the true full moon, which in
general, occurs one or two days earlier. From these conditions it follows,
that if the paschal full moon fall on Saturday, the 21st of March, then
Easter will happen on the 22d, its earliest possible date. For if the full
moon arrive on the 20th, it would not be the paschal full moon, which
cannot happen before the 21st, consequently the following moon is the
paschal full moon, which happens 30 days after the 20th of March, which is
the 19th of April. Now, if in this case the 19th of April is Sunday, then
Easter must be celebrated the following Sunday, or the 26th of April.
Hence, Easter Sunday cannot happen earlier than the 22d of March, or later
than the 26th of April.
The observance of these rules renders it necessary to reconcile three
periods which have no common measure, namely, the week, the lunar month,
and the solar year; and as this can be done only approximately, and within
certain limits, the determination of Easter is an affair of considerable
nicety and complication. It has already been shown that the lunar cycle
contained 6939 days and 18 hours; also, that the exact time of 235
lunations is 6939d, 16h, 31m, 14.45s. The difference, which is 1h, 28m,
45.55s., amounts to a day in 308 years, so that at the end of this time
the new moons occur one day earlier than they are indicated by the Golden
Numbers. During the 1257 years that elapsed between the Council of Nice
and the reformation, the error had accumulated to four days, so that the
new moons, which were marked in the calendar as happening, for example, on
the 5th of the month, actually fell on the 1st.
It would have been easy to correct this error by placing the Golden
Numbers four lines higher in the new calendar, but the suppression of ten
days had already rendered it necessary to place them ten lines lower, and
to carry those which belonged, for example, to the 5th and 6th of the
month, to the 15th and 16th. But supposing this correction to have been
made, it would have become necessary, at the end of 308 years, to place
them one line higher, in consequence of the accumulation of the error of
the cycle to a whole day. On the other hand, as the Golden Numbers were
only adapted to the Julian calendar, every omission of the centenary
intercalation would require them to be placed one line lower, opposite the
6th, for example, instead of the 5th of the month, so that, generally
speaking, the places of the Golden Numbers would have to be changed every
century. On this account Lilius thought fit to reject the Golden Numbers
from the Calendar, and supply their places by another set of numbers
called Epacts, the use of which we shall now proceed to explain.
Epact, (Greek _epaktos_, added or introduced). The excess of the solar
year beyond the lunar, employed in the calendar to signify the moon's age
at the beginning of the year. The common solar year consisted of 365 days
and the lunar year only 354 days, the difference is eleven; whence, if a
new moon fall on the first day of January in any year, the moon will be
eleven days old on the first day of the following year, and twenty-two
days old on the first of the third year. The numbers eleven and twenty-two
are therefore the epacts of those years respectively. Another addition of
eleven gives thirty-three for the epact of the fourth year; but in
consequence of the insertion of the intercalary month in each third year
of the lunar cycle, this epact is reduced to three; for 33 - 30 = 3. In
like manner the epacts of all the following years of the cycle are
obtained by successively adding eleven to the epact of the former year,
and rejecting thirty as often as the sum exceeds or equals that number.
In order to show how the epacts are connected with the Golden Numbers, let
a cypher represent the new moon on the first day of January in any year,
then the epacts and Golden Numbers for a whole lunar cycle would be
represented thus:
1 2 3 4 5 6 7 8 9
0 11 22 3 14 25 6 17 28
10 11 12 13 14 15 16 17 18 19
9 20 1 12 23 4 15 26 7 18
But the order is interrupted at the end of the cycle; for the epact of the
following year found in the same manner would be 18 + 11 = 29, whereas it
ought to be a cipher to correspond with the moon's age and the Golden
Number 1. The reason for this is, that the intercalary month, inserted at
the end of the cycle, contains only twenty-nine days instead of thirty;
whence, after 11 has been added to the epact of the year corresponding to
the Golden Number 19, we must reject twenty-nine instead of thirty, in
order to have the epact of the succeeding year; or, which comes to the
same thing, we must add twelve to the epact of the last year of the cycle,
and then reject thirty as before. Thus, 18 + 12 = 30; 30 - 30 = 0; the
cipher corresponding with the Golden Number 1.
This method of forming the epacts might have been continued indefinitely
if the Julian intercalation had been followed without correction and the
cycle had been perfectly exact; but as neither of these suppositions is
true, two equations or corrections must be applied, one depending on the
error of the Julian year, which is called the solar equation; the other on
the errors of the lunar cycle, which is called the lunar equation. The
solar equation occurs three times in 400 years, namely, in every secular
year which is not a leap-year; for in this case the omission of the
intercalary day causes the new moons to arrive one day later in all the
following months, so that the moon's age at the end of the month is one
day less than it would have been if the intercalation had been made, and
the epacts must accordingly be all diminished by unity. Thus, the epacts
11, 22, 3, 14, etc., become 10, 21, 2, 13, etc.
On the other hand, when the time by which the new moons anticipate the
lunar cycle amounts to a whole day, which, as we have seen, it does in 308
years, the new moons will arrive one day earlier and the epacts must,
consequently, be increased by unity. Thus, the epacts 11, 22, 3, 14, etc.,
in consequence of the lunar equation, becomes 12, 23, 4, 15, etc. In order
to preserve the uniformity of the calendar, the epacts are changed only at
the commencement of the century; the correction of the error of the lunar
cycle is therefore made at the end of 300 years. In the Gregorian calendar
this error is assumed to amount to a day in 312-1/2 years, or eight days
in 2500 years, an assumption which requires the line of epacts to be
changed seven times successively at the end of each period of 300 years,
and once at the end of 400 years; and from the manner in which the epacts
were disposed at the reformation, it was found most correct to suppose one
of the periods of 2500 years to terminate with the year 1800.
The years in which the solar equation occurs, counting from the
reformation, are 1700, 1800, 1900, 2100, 2200, 2300, 2500, etc. Those in
which the lunar equation occurs are 1800, 2100, 2400, 2700, 3000, 3300,
3600, 3900, after which 4300, 4600, and so on. When the solar equation
occurs, the epacts are diminished by unity; when the lunar equation
occurs, the epacts are augmented by unity; and when both equations occur
together, as in 1800, 2100, 2700, etc., they compensate each other, and
the epacts are not changed.