Some time in the last days of July 1283 the future unfortunate/catastrophic Edward II was conceived. That he was born at Caernarfon is, of course, well known. While the story that he was presented to the Welsh as their prince, who could speak no word of English, is of course apochryphal, there are very good grounds to suppose that his birth in April 1284 was staged there quite deliberately - the new English prince born in the new English castle, to remind the Welsh who was now in control.
But there is also a theory (mentioned, for example, by Kathryn Warner on her excellent Edward II blog: http://edwardthesecond.blogspot.co.uk/) that the conception of Edward II took place - and was possibly even similarly stage managed - at Caernarfon. A fascinating thought, but credible?
Well let's start with the evidence. Firstly Edward "of Caernarfon" was born on 25 April 1284. If you feed that information into a conception date calculator, it will tell you that Edward was conceived on 30 July 1283. A reference to the Itinerary of Edward I shows that he was indeed at Caernarfon from mid way through July until the day 30th of July itself, with only one day at Rhuddlan in that time. He then drops off the record for two days, before resurfacing on 2 August in Anglesey. The period 6 to 21 August is then spent back in the vicinity of Caernarfon, with 13-1 and 18-20th actually spent there. At the other end of the equation Edward and Eleanor arrived at Caernarfon at the beginning of April 1284, some 25 days before young Edward's birth. For Eleanor this was a fairly long time - she was often to be found travelling to within about two weeks of the baby's arrival. This may suggest taht Edward was expected earlier than 25th, though at the same time the fact that the court was staying in Wales, rather than travelling around the country may have given her leisure for a longer than usual pause before the birth.
So the evidence suggests that it is very possible indeed that young Edward was indeed conceived at Caernarfon, in the wooden apartments which had only just been put up. Equally, though he may have been conceived on Anglesey - at Aberffraw, the base of the dynasty of Kings of Gwynedd which Edward had just displaced. Either way, the location of the conception can be seen as significant.
The question of the conception being stage managed though, is more of a reach. On the one hand, it certainly is unusual to see Edward and Eleanor stay in one place for more than about ten days - unless a baby was actually being born. What is more the fact that the stay (on and off) lasted almost exactly a month is suggestive. However on balance the stage managed theory seems implausible, for a few reasons. Firstly, babies cannot so easily be conceived to order. And although Eleanor had been notably fertile, she was now nearly forty three, and had borne at least fifteen children. There were simply no guarantees that she would bear any more children, still less that she would conceive that month. But also there is another, much more powerful reason for Edward and Eleanor ro be on site at Caernarfon: the castle imperatively required a good deal of planning input. The idea of putting a castle here had only been arrived at a couple of months before. This, therefore, was the period at which the plans would be drawn up, spaces marked out, and detailed discussions held to allow the on site team to progress the plan over the coming months - and provide the rudiments of a castle as soon as possible. And Caernarfon was to be no simple castle - architecturally it was charged with all sorts of significances, which must have been the product of much planning. Amongst these is the form of the Eagle Tower (see Extras page).