1.In 1582, scientists pointed out that the calendar was 10 days behind the sun

2.By the year 1582, scientists pointed out that the calendar was 10 days behind the sun.

I wanted to know the difference between "by the year 1582" and "in 1582".

  • Semantics aside, there is also a difference in tense required. (1) is Past Simple; scientists pointed out (they did it once, and in that year). (2) Should be in Past Perfect Simple; scientists had pointed out (there is a vagueness about the exact time - probably happened before that exact year). Jun 23, 2017 at 7:55

5 Answers 5


"In 1582" means that the event happened in 1582, plain and simple.

"By the year 1582" means the event happened sometime during or before the year 1582. (This would be the more apt wording if we weren't sure exactly when the event took place, but we knew that it happened no later than 1582.)

  • 2
    Normally I would agree with your reasoning, but it seems that in this particular case the second statement also means that the scientists did indeed point it out in 1582. Although this particular example (in the OP) is discussing something that happened progressively, that is, leading up to that year. The sun became increasingly farther behind the calendar until finally scientists pointed it out in 1582. So, as you say "the event", I would take that to be the sun being behind the calendar, not the scientists pointing it out, which presumably happened in exactly that year.
    – Octopus
    Jun 23, 2017 at 6:49
  • 2
    @Octopus - No. The phrases as worded in the question mean exactly what J.R. has said. You could say "By the year 1582 the calendar was 10 days behind the sun" to show the progression, but the phrases in the question are about a specific single event (the scientists pointing out the situation) which was not a progressive event.
    – AndyT
    Jun 23, 2017 at 8:57
  • 3
    If I saw the phrase "By the year 1582, scientists pointed out that ..." I would take it to mean that historians are not certain exactly when the discovery was decisevly understood and propagated, but it is known that in 1582 (at the latest) the discovery was known. "In 1582, scientists pointed out ...." would indicate the year of discovery was precisely known, but often statements like this are invalidated by later discoveries so historians often prefer the former wording. Jun 23, 2017 at 13:46
  • 1
    To be fair, I'd say that as worded, the second example is slightly questionable grammar. If I were using that option, I'd have worded it as "By 1582, scientists had pointed out..." because as written, it's linking a continuous period of time to a discrete event, which doesn't quite map. Jun 23, 2017 at 13:57
  • 1
    I think perhaps something like “The second option says that we know scientists in 1582 were pointing this out, but does not rule out the possibility that there were scientists before 1582 who also pointed it out.” It might clear up some of the confusion that Octopus and anaximander have about why a continuing tense is being used here.
    – KRyan
    Jun 23, 2017 at 15:23

The "core" sense of by is near, beside, but in contexts where movement (through space or time) is relevant, there's a metaphorical extension to this definition. From the full OED...

by - Sense 21a:
Marking the completion of the time required or assigned for the performance of an action

What this means is that in contexts such as You should understand this sentence by now, the implication of including by is that you should have had sufficient time to understand it (with the further implication that the amount of time since the point when you started trying to understand it is relatively large). If by hadn't been included (You should understand this sentence now) , that allusion to "excessive, more than sufficient" time largely disappears (the speaker may simply be alluding to the fact that since he's only just explained things, you should understand it now even if you might not have done half-an-hour ago).

This metaphorical use of by can be extended to locational referents provided they're contextually linked to time because there's movement through points in space (in the same way the movement of the hands of a clock reflect movement forwards through time). Thus, for example,...

Because the lift wasn't working, I started up the stairs to my tenth floor penthouse apartment. But by the fourth floor I was absolutely exhausted, and needed to sit down and rest.

Thus in OP's specific context, by the year 1582 implies that either scientists had already been spending time preparing to say something about "calendar drift", OR (more probably) it's just an oblique reference to the fact that the discrepancy between "calendar time" and real-world time as measured by the changing of seasons was becoming progressively larger every year, and could no longer be ignored.

Without by, one might assume the scientists only just noticed and publicised the discrepancy in 1582 (with no implication that any preceding events or actions actually led up to this situation).


There is a subtle but real difference between the use of "by the year" and "in the year 1582…" If you say "by the year 1582," you are indicating that before that year scientists didn’t point out that knowledge, however, the evidence was mounting and they were coming closer to that point in time to be able to do so (due to having enough evidence, or acceptance or for whatever reason) and, in 1582, there was a sense of completion that enabled them to point out their knowledge.

When you say "in the year 1582…" the meaning is that the action was done sometime that year. The sense is that it’s not known exactly when during that year, but sometime that year.

In "in the year 1582…" there is a bit of an emphasis that that was the year the scientist pointed it out whereas "by the year" gives the feeling that something was in the process of changing or coming about, and it finally did (change or come about) in that year.

  • Yes, exactly. This critical point is missing from the answers above.
    – Boaz
    Jun 22, 2017 at 22:59
  • With the wording of the two phrases in the question, this answer is wrong. However, it does have an important point; it just only works with rewording. You could say "By the year 1582 scientists had enough evidence to point out that the calendar was 10 days behind the sun."
    – AndyT
    Jun 23, 2017 at 8:54

"By the year" here means "before the year" or "no later than the year":

  • By the year 1582, scientists pointed out that the calendar was 10 days behind the sun. (Before the year 1582 starts)

The scientists could have been working any period of time (we don't know for sure) but no later than 1582 they pointed out that the calendar was 10 days behind the sun.

You could also say "By the end of the year" to refer to a period before the end of a specific year; no later than the end of a specific year.

"In the year" means exactly within the period of the year; during the year (not before and not after).

  • In 1582, scientists pointed out that the calendar was 10 days behind the sun. (Only within the year 1582 and not within any other year)
  • 4
    I can't figure out why you've included the contents of your first sentence, let alone as the first sentence.
    – JPhil
    Jun 22, 2017 at 19:14
  • @JPhil I guess as a reminder. We, Russians, are strange people! Jun 22, 2017 at 19:53
  • 1
    I'm suggesting an edit to remove the misleading first sentence. Jun 23, 2017 at 0:12
  • This answer contradicts with the selected answer. Here "by the year 1582", as interpreted by Steve, represent before 1582 while the selected answer said it means during and before 1582. Who is wrong or right? Jun 25, 2017 at 2:21
  • @user2720402 "by the year" doesn't mean during. Jun 25, 2017 at 6:23

As others have said, if the second sentence had been:

"By the year 1582, scientists had pointed out that the calendar was 10 days behind the sun."

then it would mean that they pointed it out no later than 1582. In your sentence, though, "by the year" is associated with the the calendar drifting, not with the scientists' statement. It could be rephrased to:

"Context about how the calendar had been moving out of sync with the sun... Scientists pointed out that in 1582 the calendar was 10 days behind the sun."

The scientists either pointed this out in 1582, or were historians who pointed it out years later, depending on the previous context.

  • I don't disagree with anything in your analysis of tense usage, and I'd probably have upvoted if OP's question had been about Past Perfect. But it isn't, so technically speaking this is Not An Answer. I'd also point out (not down to you, of course! :) that actually there were no "scientists" by that name in 1582, since the word scientist didn't exist in English until mid-C19. Jun 23, 2017 at 12:09

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