Chronology of the Anne Books
Rilla of Ingleside begins in June 1914 (RoI, ch 1, 1st page). It is the same day that Archduke Ferdinand is assassinated, which makes it 28th June. Rilla says (RoI, ch 2, last page) that she will be fifteen next month (July 1914) so she was born in July 1899. Jem is aged 21. (RoI, ch 1, 5th page).
It is May when Rainbow Valley begins (RV, ch 1), Rilla is six years old and Jem is 13 (RV, ch 3). Rilla will therefore be seven in July, and the year must be 1906. The Meredith children's ages are: Jerry 12, Faith 11, Una 10 and Carl 9 (RV, ch 2). The twins (Nan and Di) were ten years old at this time (RV, ch 3), and so were born some time between June 1895 and May 1896, depending on whether they were just 10 or nearly 11.
In AHoD, it is June when 'Leslie returns home' (AHoD, ch 33). Jem is born in the following chapter, though a date is not given. It must either be June or shortly after. It can't be much later because in chapter 35, when Anne had 'come downstairs again' after Jem's birth (perhaps about 3 weeks to a month later) there are some indications that we are still in high summer — say August at the latest. Susan is more concerned about the dry spell than about politics, and Captain Jim 'seldom went out in his boat that summer'. All this suggests that Jem was born in June or July.
If Jem was born before June 28th, then at the beginning of RoI he must be only just 21. If his birthday is later than this, he must be nearly 22, at the start of RoI. The first possibility can be ruled out as follows. Rilla's birth occurs some time in AoI, which begins 'nine years since [Anne] went away [from Green Gables]' (AoI, ch 1). Rilla is therefore born at least 9 years after Anne and Gilbert were married, which makes it at least 8 years after Joyce was born and at least 7 years after Jem was born. If Jem is at least 7 years older than Rilla, he must be at least 15 + 7 = 22 in 1914.
I conclude that Jem's birthday is some time in July in the year 1914 - 22 = 1892. AoI must begin in 1914 - 15 = 1899. This would make 1890 the year Anne and Gilbert were married. AHoD, ch 4 speaks of a 'September breeze' on the morning of Anne's wedding, and ch 8 looks back over the four week honeymoon and calls it 'that September'. According to AHoD, ch 2, the wedding took place when she was 25 years old, 14 years after she came to Green Gables. Anne was therefore born in 1890 - 25 = 1865. Her birthday is in March (AoA, ch 13). In AoGG, ch 8, Marilla tells Anne there are only two weeks of school left before the summer vacation. I suppose that means it was some time in June, so that Anne must have arrived in Green Gables some time in May or June.
Returning to AoI, in ch 2 there were 'still plenty of June lillies', which suggests late June or early July. There are a few chapters before Rilla is born (July 1899), which suggests that June is more likely than July for the start of the book. At this stage, Shirley is two years old (AoI, ch 3), so he must have been born in late 1896 or early 1897. Walter is six (AoI, ch 7), so he was born in late 1892 or early 1893. But if Jem was born in July 1892, then Walter must have been born towards the end of that range of dates, say about June 1893.
This gives the following dates.
|March 1865||-||Anne born in Bolingbroke, Nova Scotia|
|May/June 1876||11||Anne arrives at Green Gables|
|September 1880||15||Anne goes to Queens|
|September 1881||16||Anne begins teaching at Avonlea|
|September 1883||18||Course at Redmond begins|
|Summer 1887||22||Anne and Gilbert engaged, Anne becomes Principle at Summerside|
|September 1890||25||Anne and Gilbert marry and move to Four Winds|
|June/July 1891||26||Joyce born and dies|
|July 1892||27||Jem born|
|June 1893||28||Walter born|
|Late 1894 / early 1895||29/30||Nan and Di born|
|Late 1896 / early 1897||31/32||Shirley born|
|June 1899||34||Anne of Ingleside begins|
|July 1899||34||Rilla born|
|Feb - May 1906||40-41||Anne and Gilbert visit Europe|
|May 1906||41||Rainbow Valley begins|
|28th June 1914||49||Rilla of Ingleside begins|
There is a slight inconsistency between the books, over the question of Marilla's age. RV, ch 2 says that Marilla is 85. Anne's age would have been 25 (her age at marriage) plus the (roughly) two years before Jem was born, plus 13 (Jem's age at the start of RV). This makes a total of 40, so that Marilla is 85 - 40 = 45 years older than Anne. On the other hand AotI, ch 22 says 'Marilla felt that of her sixty years, she had lived only the nine that had followed the advent of Anne'. Nine years after Anne arrived, she would have been 11 + 9 = 20, so Marilla would have been 20 + 45 = 65 years old at this point, not 60. We can only conclude that 'of her sixty years' is using very round figures — by no means unreasonably, however.