When is the Twelfth not the Twelfth?

When it's the Thirteenth!

With the Twelfth of July on a Sunday this year, the Orange parades have been deferred until the next day. It led to some confusion about the lighting of the Eleventh Night bonfires - Saturday or Sunday night? I've never been to a bonfire, and yet for many, it's an essential part of the culture. The closest we ever got was sitting watching the Thornhill bonfire from a distance on the other side of the A1 dual carriageway.

But why bonfires? In some ways, those lighting the bonfires are celebrating the mobile phone of the Williamite era. Nowadays we're used to twenty-four hour news channels, mobile phone coverage and even Twitter to know what's going on in the world. But back in 1690, as William took to the battlefield on the green grassy slopes of the Boyne, how would the folks at home know who had won? Twitter is restricted to 140 characters, but the bonfire communicated one word: victory!

The word could spread quickly, from one hilltop to the next, with beacons blazing in the night sky. Ancient communications being continued, only now it's from one housing estate to another! That's why the commemoration of the Battle of the Boyne is (normally) held on the Twelfth. You see, the Battle of the Boyne was fought on the 1st July 1690 under the Julian calendar. In 1750, when Britain adopted the Gregorian calendar, ten days were added to bring Britain in line with Europe, which makes the 1st July Old Style into 11th July New Style. The bonfires on the evening of the 11th are as if the word is just reaching the towns and villages, and then the celebrations and processions are held on the next day, the Twelfth, unless it's on a Sunday.