I have espionage, yet can build IA

[kailhun]

One of the edits to my .bic is Espionage in the ancient era (after literature to be precise). In my current game, I developed Espionage but couldn't build the IA.
After a couple of turns, I suddenly got the 'The people want to build XXX' three times. One of these was the IA. What gives? What was the trigger?
BTW I'm the Romans and had just attacked the Egyptians (first battle in the game). Was this it?

Robert