In 1539 Luther wrote his comments about the date of
  Easter.
  The Counsel of Nicaea chose the date in 325.
  Luther's Works Vol. 41, pages 61-64
  However, one ember from these wooden articles has kept on glowing, namely,
  the one about the date of Easter. We do not observe this article quite
  correctly either (as the mathematicians and astronomers point out to us)
  because the equinox in our time is far different than in that time, and our
  Easter is often celebrated too late in the year. Long ago, shortly after the
  days of the apostles, the quarrel about the date of Easter broke out; and over
  this trifling and unnecessary matter the bishops accused one another of heresy
  and excommunicated one another, which was a sin and a shame.
  Several advocated observing it on the same day as the Jews, according to
  the law of Moses; others, lest they be regarded as Jewish, wanted to observe
  it on the following Sunday. The bishop of Rome, Victor, who also became a
  martyr, excommunicated all the bishops and churches in Asia approximately one
  hundred and eighty years before this council for not adhering to the same
  Easter date as he did. So early did the Roman bishops make a grab for majesty
  and power! But Irenaeus, bishop of Lyons, in France, who had known Polycarp, a
  disciple of St. John the Evangelist, reprimanded him and settled the quarrel
  so that Victor had to leave the churches in peace.
  That is why Constantine also had to take up this matter and help to settle
  it in the council. He decreed that the same Easter date should be observed
  throughout the world; read the Tripartita, Book IX, chapter 38. I suppose that
  the present again calls for a reform and correction of the calendar in order
  to assign Easter its proper place. But no one should undertake that except the
  exalted majesties, emperors and kings, who would have to unanimously and
  simultaneously issue an order to all the world saying when Easter is
  henceforth to be celebrated. Otherwise, if one country were to start without
  the others, and worldly events, such as markets, fairs, and other business,
  were governed by the present date, the people of the country would appear at
  the markets of another country at the wrong time, which would result in wild
  disorder and confusion in everything. It would be very nice, and easy to do,
  if the high majesties would want to do it, since all the preparatory work has
  been done by the astronomers and all that is needed is a decree or command. In
  the meantime we hold to the flickering ember from the Nicene council that
  Easter is to be kept on a Sunday; meanwhile the date may wobble back and
  forth, for they are called "movable festivals" I call them wobbling
  festivals since the Easter day, with its associated festivals, changes every
  year, coming early in one year, late in another, and not on a certain day like
  the other festivals.
  This wobbling of the festivals is due to the fact that the ancient fathers
  (as was said) in the very beginning wanted to have Easter at the time
  established by Moses, namely, in the full moon of March, nearest the equinox;
  and yet they were unwilling to Judaize entirely, or to keep Easter with the
  Jews on the day of the full moon, so as Christians they dropped the law of
  Moses and took the Sunday after the March full moon. Thus it happened last
  year, 1538, that the Jews observed their Easter on the Saturday after
  Invocavit-as our church calls it-that is, about five weeks before we observed
  our Easter. Now the Jews laugh about that and ridicule us Christians, saying
  that we do not keep Easter right and that we do not even know how to keep it
  right, thus hardening their unbelief. This then irritates our people, and they
  would gladly see the calendar corrected by the exalted majesties, for without
  their co-operation this is impossible to do and still less advisable.
  In my opinion this experience with Easter is nicely described by Christ in
  Matthew 9 [:16-17], "No one puts a piece of unshrunk cloth on an old
  garment, for the patch tears away from the garment, and a worse tear is made.
  Neither is new wine put into old wineskins; if it is, the skins burst, and the
  wine is spilled, and the skins are destroyed." They want to retain a part
  of the old law of Moses, namely, to pay heed to the full moon of March-that is
  the old garment. Then (as Christians delivered from the law of Moses by
  Christ) they do not wish to be subject to that same day of the full moon, but,
  instead want to take the following Sunday-that is the new patch on the old
  garment. That is why the everlasting squabble and the constant wobbling have
  to date caused much mischief in the church, and it will have to, until the end
  of the world, with books appearing without measure or end on this subject.
  Christ has permitted this to go on for a special reason, as he always proves
  his strength in weakness and teaches us to recognize our own weakness.
  How much better it would have been if they had let Moses' law regarding
  Easter die altogether and had retained nothing of the old garment. For Christ,
  to whom this law applied, has annulled it completely, killed it, and buried it
  forever through his passion and resurrection. He rent the veil of the temple
  and subsequently broke up and destroyed Jerusalem with its priesthood,
  principality, law, and everything. They should instead have reckoned and noted
  the days of the passion, the burial, and the resurrection by the course of the
  sun and set a fixed date for these, as they did with Christmas, New Year's,
  the day of the Magi, Candlemas, the Annunciation of Mary, the Feast of St.
  John, and other festivals, which they call fixed, not wobbling festivals. Then
  one would know every year for certain when the day of Easter and its
  associated festivals must come, without such great difficulty and disputation.
  Well, you say, Sunday should be held in reverence for the sake of Christ's
  resurrection-it is therefore caned dies Dominica-and Easter is assigned to
  that day, since Christ rose on the day after the Sabbath (which we now can
  Saturday). This is certainly an argument that moved them, but since dies
  Dominica does not mean Sunday, but the Lord's day, why shouldn't any day on
  which Easter had fallen be called dies Dominica, the Lord's day? Is not
  Christmas also dies Dominica, the Lord's day, that is, the day on which the
  Lord's special event, his birth, is celebrated, which does not fall on a
  Sunday every year? Yet it is still called Christ's day, that is, the Lord's
  day, even if it falls on a Friday, because it has a fixed letter in the
  calendar calculated by the course of the sun. Just so could Easter have a
  fixed letter in the calendar, whether it came on Friday or Wednesday, as
  happens with Christmas. That way we would be well rid of the law of Moses with
  its full moon of March, just as no one asks today whether the moon is full or
  not at Christmas, but we adhere to the days as calculated by the sun 's course
  and ignore the moon.
  One might argue that since the equinox (as the astronomers point out) is
  movable, and the years in the calendar move too slowly and so do not keep pace
  with it, and the more years go by the worse it is, after a while the equinox
  would move further and further from a fixed Easter day, as it would also move
  further and further from the day of St. Philip and St. James, and from other
  festivals. What does it matter to us Christians? Even if our Easter should
  coincide with the day of St. Philip and St. James (which, I hope, will not
  happen before the end of the world) and move still further, we still celebrate
  Easter daily with our proclamation of Christ and our faith in him. It is
  enough to celebrate Easter once annually on a special day as an obvious,
  public, and perceptible reminder, not only because it affords an opportunity
  to discuss more thoroughly the history of the resurrection before the common
  people, but also because it represents a definite season according to which
  people may arrange their various business affairs, such as the seasons of St.
  Michael, St. Martin, St. Catherine, St. John, SS. Peter and Paul, etc.
  But this has been neglected from the very beginning; we cannot make any
  changes because the fathers did not initiate a change. The old garment with
  its great tear has stayed on and on, and now it may as well stay until the
  Last Day, which is imminent anyhow. Since the old garment has endured being
  patched and torn for approximately fourteen hundred years, it may as well let
  itself be patched and torn for another hundred years; for I hope that
  everything will soon come to an end. And if the Easters have wobbled back and
  forth for about fourteen hundred years now, they may as well continue to
  wobble for the short time still remaining, since no one will do anything about
  it anyway, and those who would like to do something cannot.
  I am entering into this lengthy and needless chatter solely for the purpose
  of expressing my opinion, in case several sects in the course of time dare
  arbitrarily to move the Easter festival to another date than that which we now
  observe. And I believe if the Anabaptists had been sufficiently versed in
  astronomy to understand these things, they would have rushed in headlong, and
  (as is characteristic of the sect) introduced something entirely new and
  observed Easter on a different day than the whole world. But since they were
  unlearned in the sciences, the devil was unable to employ them as that kind of
  instrument or tool. Therefore, I advise that one let Easter come as it now
  comes, and keep it as it is kept now, and let the old garment be patched and
  torn (as was said); and let Easter wobble back and forth until the Last Day,
  or until the monarchs, in view of these facts, unanimously and simultaneously
  change it.
  For this is not going to kill us, nor will St. Peter's bark suffer distress
  because of it, since it is neither heresy nor sin (though the ancient fathers
  in their ignorance regarded it as such and dubbed each other heretics and
  excommunicated each other over it), but only an error or solecism in
  astronomy, which serves temporal government rather than the church. If the
  Jews mock us, as though we were doing it out of ignorance, then we, in turn,
  mock them far more because they adhere so rigidly and vainly to their Easter,
  and do not know that Christ fulfilled, annulled, and destroyed all that
  fifteen hundred years ago. For we do it willingly, knowingly, not out of
  ignorance. We would know quite well how to keep Easter according to the law of
  Moses-far better than they know it. But we will not and must not do it, for we
  have the Lord over Moses and over all things, who says, "The Son of man
  is lord of the sabbath" [Matt. 12:8]. How much more is he the Lord over
  Easter and Pentecost, which, in the law of Moses, are less than the sabbath,
  which is on the tables of Moses, while Easter and Pentecost are outside the
  tables of Moses? Furthermore, we have St. Paul, who flatly forbids any one to
  be bound to holidays, feasts, and anniversaries of Moses, Galatians 4 [:10]
  and Colossians 2 [:16].
  We therefore have and must have the power and the freedom to observe Easter
  when we choose; and even if we made Friday into Sunday, or vice versa, it
  would still be right, as long as it were done unanimously by the rulers and
  the Christians (as I said before). Moses is dead and buried by Christ, and
  days or seasons are not to be lords over Christians, but rather Christians are
  lords over days and seasons, free to fix them as they will or as seems
  convenient to them. For Christ made all things free when he abolished Moses.
  However, we will let things remain as they now are, since no peril, error,
  sin, or heresy is involved, and we are averse to changing anything needlessly
  or at our own personal whim, out of consideration for others who observe
  Easter at the same time as we do. We know we shall attain salvation without
  Easter and Pentecost, without Friday and Sunday, and we know that we cannot be
  damned-as St. Paul teaches us-because of Easter, Pentecost, Sunday, or Friday.
  But to get back to the council, I say that we make too much of this ember
  from the Nicene council. The pope and his church subsequently made of this not
  only gold, silver, and precious stones, but also a foundation, that is, an
  article of faith, without which we could not be saved; and they all call it a
  commandment of, and an act of, obedience to the church. That makes them far
  worse than the Jews, for the Jews do have the Mosaic text commanded by God at
  that time in their favor, while these have nothing but their own fancy on
  their side; they come along and want to make a new garment out of the old rags
  of Moses. They claim that they are obeying Moses, though their doctrine is
  sheer fantasy, a dream about Moses who has long been dead and, as Scripture
  declares, buried by the Lord himself [Deut. 34:6] (that is, by Christ), so no
  one has ever found his grave. They want to reproduce the living Moses by magic
  before our eyes, but they fail to see, as St. Paul says in Galatians 5 [:3],
  that if they wish to keep one part of Moses they must keep all of Moses.
  Consequently, if they regard it a part of Mosaic law to set the date of Easter
  according to the full moon in March, they must also keep the whole law
  concerning the paschal lamb and forthwith become Jews, keeping a bodily
  paschal lamb with them. If not, they must discard it all, the full moon too,
  with all the rest of Moses; or in any case not regard this as necessary for
  salvation like an article of faith, which is what I believe the fathers in
  this council (especially the best ones) did.