De Montfort, Llywelyn ap Gruffydd and 'Democracy Day'
Take your pick: 50 years since Winston Churchill died, 800 years since Magna Carta, 200 years since Waterloo.
Tomorrow is also the 750th anniversary of the de Montfort parliament convoked by Simon de Montfort, the first nobleman to seize power and govern the country.
It is seen as the first English parliament as it was the first with a house of commons to which knights from the counties and burgesses from the towns were summoned.
Historian Professor David Carpenter notes that de Montfort may have opposed King Henry III under the umbrella of "England for the English" even though he wasn't English himself. There was also a strong Welsh dimension to his power grab.
Prof Carpenter told me: "One of the bases of Montfort's power was his alliance with Llywelyn who was very soon to be recognised as prince of Wales. In fact Montfort himself, very soon after the parliament, affirmed that alliance with Llywelyn by actually recognising him as just that, recognising him as prince of Wales and that laid the foundation for the later treaty of Montgomery in which King Henry III did the same.
"The result was there was a very, very large contingent on Montfort's side at the final, fatal battle of Evesham and as they marched out of Evesham this Welsh contingent of footsoldiers let out a great shout which shook the heavens. And for many of them it was the last shout of their lives because they were then massacred in the battle in which Montfort himself was also gruesomely killed."
The BBC is today marking the 750th anniversary of the de Montfort parliament in what we are calling "Democracy Day". As the BBC puts it: "Across radio, TV and online, the BBC will look at democracy past and present, ask how democratic we are, and encourage debate about democracy's future."
I'll be making my own small contribution through BBC Parliament. Reporting the National Assembly for Wales is normally above my pay grade, but I'll be joining a discussion that endeavours to explain the work of all the parliaments of the UK. We hope to cover the assembly's petitions committee live. Do join me - we're on between 9:30 and 11:30.
As "Democracy Day" draws to a close, at 11pm, Sean Curran and Susan Hulme will present a special one-hour edition of Today in Parliament on Radio 4. Unusually, TiP, as it's known, will feature coverage of the UK's other parliaments. Tune in for Nick Servini's take on first minister's questions from Cardiff Bay.