[Phil Steer]

Please forgive me if this a really dumb question.
When dates are given for events that occurred prior to the adoption of the Gregorian calendar, are the dates those that would have been used at the time, or are they converted to Gregorian dates?
For example, did the 'Gunpowder Plot' actually take place on 5 November 1605 (i.e. is that the date that the plotters would have recognised) or is that the Gregorian-equivalent date?
I feel sure that the answer must be that the dates specified are those that were used at the time, but it would be good to have that confirmed.
If so, that leads on to one other question, which is what happens when writing about events that concern two countries that adopted the calendar at different times?
For example, when the Spanish Armada sailed, Spain had adopted the Gregorian calendar, but Britain hadn't, so the date would be different in the two countries. Which date would be used when writing about the event?
Many thanks.

[Dave Musgrove]

Very good question Phil. I think I'm right in saying that 5 November was the actual date in the Julian Calendar, and so was a date that the plotters would have recognised.
The calendar was changed to the Gregorian version in Britain in 1752, so in that year, we famously lost the days as a result of that.
There's a good synopsis of what happened at the National Maritime Museum website here http://www.nmm.ac.uk/explore/astronomy- ... leap-years
On your last point regarding international differences (the Gregorian calendar was adopted in Europe in 1582), there are conversion tables available to tally up the different dates and I'd venture that historians would tend to talk about the calendar in use in the country they are mainly talking about, or based in.

[Phil Steer]

Many thanks for the clarification. Merry Christmas!