Source for Culture timeline

Question

I've been an Iain Banks fan for a long long time, but for the most part haven't haven't tried to read the Culture books in any particular order, and have left myself at least a few for the future. I'm now starting on the original "trilogy".

Banks can be comic and I got a chuckle out of this Culture-Earth timeline, which was cited in a Q&A here -- but I am seriously interested in the source or justification. By my reading of the Culture books there is no concrete reference to the idea that they are even in the same galaxy as ours, much less that there's an overlapping timeline to our own history. My question is two-fold:

• Where did Banks express this?
• Are there any concrete references in any of the novels that refer to/make significance of this correpondence? Or that the galaxy referred to is the Milky Way?

I recognize he does use the term "human" synonymously with "humanoid" as a convention, and please no answers that claim that as the only evidence.

Answer 1

In the novella The State of the Art the Culture sends a mission to Earth in the 1970s.

Answer 2

Consider Phlebas includes some appendices which "have been extracted from A Short History of the Idiran War (English language/Christian calendar version, original text AD 2110, unaltered)," which in turn was "part of an independent, non-commissioned but Contact-approved Earth Extro-Information Pack."

It establishes several key dates in the Idiran-Culture War:

• AD 1267 - The first Idiran-Culture dispute
• 1288 - The second Idiran-Culture dispute
• 1289 - The Culture constructs its first warship since the 7th Century AD
• 1307 - The third Idiran-Culture dispute, and the first machine fatalities
• 1310 - Anchramin Pit Conference secures a temporary withdrawal of forces
• 1323 - The fourth Idiran-Culture dispute
• 1327 - War is officially declared
• 1327 - Ratification of the Idiran-Culture War Conduct Agreement
• 1332 - The Homomda ally with the Idirans and enter the war
• 1333 - The War Conduct Agreement is amended outlawing the destruction of populated, non-military habitats
• 1335 - The war enters its second phase
• ca. 1362 - The Homomda sue for peace with the Culture and exit the war, leaving the Idirans to fight on alone.
• 1367 - The war in space ends
• 1375 - All planetary war is officially terminated

These dates are the Rosetta stone between Earth's Christian calendar and other books in the Culture series, which often cite landmark events in the Idiran-Culture war as a frame of reference. For instance, we know that it took 803 years for the light to reach Masaq' Orbital from the Twin Novae Battle, which occurred shortly after the Homomdan withdrawal; therefore, Look to Windward must be set some time between AD 2165 and 2170.

The same appendices also state that the Magellanic Clouds and Andromeda Galaxy lie just outside the spiral galaxy that the Culture and Idirans both inhabit.

Answer 3

As said, the State of the Art and Consider Phlebas give the keys to matching up the Culture timeline with ours and then the (in my opinion somewhat vague) references within the rest of the books can be cross-matched to give a rough timeline.

For reference: someone else has done most of the hard work and published it here on Wikia: Timeline on Culture wikia follows the Gregorian calendar

Have to admit I've not cross-checked it myself (currently working through all the books in publication order (more or less) but only at Inversions so far).

I don't believe there's any special significance between the Culture timeline and our own - indeed, according to State of the Art, we're not even worth contacting.

The second part of the second question is answered in the same story, The State of the Art - the Culture visits earth, and since the Culture is pretty much always referred to as being in 1 galaxy only, by implication, we are both in the same galaxy: the Milky Way.