In the years 1818 and 1845, Easter Day, as given by the _rules in_ 24 Geo.
II cap. 23. (known as the act for the _change of style_) contradicted the
_precept_ given in the preliminary explanations. The precept is as follows:
"_Easter Day_, on which the rest" of the moveable feasts "depend, is always
the First Sunday after the Full Moon, which happens upon or next after the
Twenty-first Day of {357} _March_; and if the Full Moon happens upon a
Sunday, _Easter Day_ is the Sunday after."
But in 1818 and 1845, the full moon fell on a Sunday, and yet the rules
gave _that same Sunday_ for Easter Day. Much discussion was produced by
this circumstance in 1818: but a repetition of it in 1845 was nearly
altogether prevented by a timely[742] reference to the intention of those
who conducted the Gregorian reformation of the Calendar. Nevertheless,
seeing that the apparent error of the Calendar is due to the precept in the
Act of Parliament, which is both erroneous and insufficient, and that the
difficulty will recur so often as Easter Day falls on the day of full moon,
it may be advisable to select from the two articles cited in the note such
of their conclusions and rules, without proof or controversy, as will
enable the reader to understand the main points of the Easter question,
and, should he desire it, to calculate for himself the Easter of the old or
new style, for any given year.
1. In the very earliest age of Christianity, a controversy arose as to the
mode of keeping Easter, some desiring to perpetuate the _Passover_, others
to keep the _festival of the Resurrection_. The first afterwards obtained
the name of _Quartadecimans_, from their Easter being always kept on the
_fourteenth day_ of the moon (Exod. xii. 18, Levit. xxiii. 5.). But though
it is unquestionable that a Judaizing party existed, it is also likely that
many dissented on chronological grounds. It is clear that no _perfect_
anniversary can take place, except when the fourteenth of the moon, and
with it the passover, falls on a Friday. Suppose, for instance, it falls on
a Tuesday: one of three things must be {358} done. Either (which seems
never to have been proposed) the crucifixion and resurrection must be
celebrated on Tuesday and Sunday, with a wrong interval; or the former on
Tuesday, the latter on Thursday, abandoning the first day of the week; or
the former on Friday, and the latter on Sunday, abandoning the paschal
commemoration of the crucifixion.
The last mode has been, as every one knows, finally adopted. The disputes
of the first three centuries did not turn on any _calendar_ questions. The
Easter question was merely the symbol of the struggle between what we may
call the Jewish and Gentile sects of Christians: and it nearly divided the
Christian world, the Easterns, for the most part, being _Quartadecimans_.
It is very important to note that there is no recorded dispute about a
method of predicting the new moon, that is, no general dispute leading to
formation of sects: there may have been difficulties, and discussions about
them. The Metonic cycle, presently mentioned, must have been used by many,
perhaps most, churches.
2. The question came before the Nicene Council (A.D. 325) not as an
astronomical, but as a doctrinal, question: it was, in fact, this, Shall
the _passover_[743] be treated as a part of Christianity? The Council
resolved this question in the negative, and the only information on its
premises and conclusion, or either, which comes from itself, is contained
in the following sentence of the synodical epistle, which epistle is
preserved by Socrates[744] and Theodoret.[745] "We also send {359} you the
good news concerning the unanimous consent of all in reference to the
celebration of the most solemn feast of Easter, for this difference also
has been made up by the assistance of your prayers: so that all the
brethren in the East, who formerly celebrated this festival _at the same
time as the Jews_, will in future conform _to the Romans and to us_, and to
all who have of old observed _our manner_ of celebrating Easter." This is
all that can be found on the subject: none of the stories about the Council
ordaining the astronomical mode of finding Easter, and introducing the
Metonic cycle into ecclesiastical reckoning, have any contemporary
evidence: the canons which purport to be those of the Nicene Council do not
contain a word about Easter; and this is evidence, whether we suppose those
canons to be genuine or spurious.
3. The astronomical dispute about a lunar cycle for the prediction of
Easter either commenced, or became prominent, by the extinction of greater
ones, soon after the time of the Nicene Council. Pope Innocent I[746] met
with difficulty in 414. S. Leo,[747] in 454, ordained that Easter of 455
should be April 24; which is right. It is useless to record details of
these disputes in a summary: the result was, that in the year 463, Pope
Hilarius[748] employed Victorinus[749] of Aquitaine to correct the
Calendar, and Victorinus formed a rule which lasted until the sixteenth
century. He combined the Metonic cycle and the solar cycle presently
described. But {360} this cycle bears the name of Dionysius Exiguus,[750] a
Scythian settled at Rome, about A.D. 530, who adapted it to his new yearly
reckoning, when he abandoned the era of Diocletian as a commencement, and
constructed that which is now in common use.
4. With Dionysius, if not before, terminated all difference as to the mode
of keeping Easter which is of historical note: the increasing defects of
the Easter Cycle produced in time the remonstrance of persons versed in
astronomy, among whom may be mentioned Roger Bacon,[751] Sacrobosco,[752]
Cardinal Cusa,[753] Regiomontanus,[754] etc. From the middle of the sixth
to that of the sixteenth century, one rule was observed.
5. The mode of applying astronomy to chronology has always involved these
two principles. First, the actual position of the heavenly body is not the
object of consideration, but what astronomers call its _mean place_, which
may be described thus. Let a fictitious sun or moon move in the heavens, in
such manner as to revolve among the fixed stars at an average rate,
avoiding the alternate accelerations and retardations which take place in
every planetary motion. Thus the fictitious (say _mean_) sun and moon are
always very near to the real sun and moon. The ordinary clocks show time by
the mean, not the real, sun: and it was always laid down that Easter
depends on the opposition (or full moon) of the mean sun and moon, not of
the real ones. Thus we see that, were the Calendar ever so correct {361} as
to the _mean_ moon, it would be occasionally false as to the _true_ one:
if, for instance, the opposition of the mean sun and moon took place at one
second before midnight, and that of the real bodies only two seconds
afterwards, the calendar day of full moon would be one day before that of
the common almanacs. Here is a way in which the discussions of 1818 and
1845 might have arisen: the British legislature has defined _the moon_ as
the regulator of the paschal calendar. But this was only a part of the
mistake.
6. Secondly, in the absence of perfectly accurate knowledge of the solar
and lunar motion (and for convenience, even if such knowledge existed),
cycles are, and always have been taken, which serve to represent those
motions nearly. The famous Metonic cycle, which is introduced into
ecclesiastical chronology under the name of the cycle of the golden
numbers, is a period of 19 Julian[755] years. This period, in the old
Calendar, was taken to contain exactly 235 _lunations_, or intervals
between new moons, of the mean moon. Now the state of the case is: