Long ago, we settled on a euphemism for the dog’s prolific urination.

He is gifted in the extreme in this area, and it is like watching a miracle as more and more liquid is emitted from a very small dog. And all in the name of a signature.

Today, for the umpty-thirteenth time, I heard someone exclaim incredulously” “But how is it possible? How can he have anything left?”

It does indeed beggar belief, and makes one fleetingly wonder if there could be any application for crossing the Sahara, accompanied by this animal.

Although, on the other hand, it may be best not to think too hard about that.

Very early on in the childrens’ young lives, we were asked, with artless candour: “Why does Macaulay do that?”

My answer was not original. But it is a particularly striking example of the lengths British middle class mothers will go to, in order to avoid the earthier realities of life.

“It’s a sort of way of signing his name, Darling”, I retorted, smoothly and with a modicum of smugness.

“Macaulay walks around a landscape,”  I added, really getting into my stride now, “but he also has a scape we can’t see: a smellscape. He is leaving a name on every lamp post between here and home, so other dogs will know exactly who he is.”

And ever since, across the years,  I have had Princesses, offspring, the world and his little brother running up to me in excruciatingly public places and shieiking: “Mummy…Auntie Kate….Felix’s Mum….Macaulay is signing his name!”

Anywhere is fair game for the dishevelled creature. While he is well houstrained, when my sister moved into her new home we narrowly avoided him christening the fireplace: because it was his, and it was new.

And this week we plumbed new depths of shame when he sidled purposefully up to a small child’s painstakingly built fortress of sand, there on a spacious beach of doggy opportunity, and cocked his leg up against the highest tower, the very pinnacle.

Territory is high on his list of priorities.

Of course, it’s not just him: humans, too choose their own way to make themselves part of their surroundings. The clifftop walk to the sea is punctuated by benches where people sit and take in the vast view across the English Channel.

Each has a small brass plate decorating its backrest. Each commemorates someone who loved this place, and who is gone now. We walk past and as we read their names, they are irrevocably linked with this place in our minds.

Signing our names: it’s a tiny kind of immortality.

In my head, over the last few days, a set of names have been repeating themselves. The names are French, and they are three hundred years old.

I found them on the castle wall the other day, and immediately rooted out a guide. Are these real, I asked?

Oh yes, was the reply. They were French officers, prisoners of war in the castle during the Wars of the Spanish Succession.

They were billeted there in an English summer in the early 1700’s and so of course it was cold and misty and inhospitable.

The great hall of the castle was fitted out in oak panelling, and POWs are not likely to respect their surroundings at the cost of their comfort. So they tore down the panelling and put in in the huge fireplace that dominates the hall, and set light to it, and burnt it.

And they were warmer, and dryer. But they hadn’t quite finished making their mark.

They set to, finding the softest stone in the hall; and then they created their own kind of immortality. They wrote their names in the stone. They drew in the stone. They even wrote poems in it, the guide enthused, although I haven’t found these yet.

I stood and gawped at these inscriptions, three centuries old, a piece of subversion and territory-marking from a war, the point of which has long been set aside on dusty historians’ shelves.

There are, of course, far older signatures in history: Roman generals used them to sign detailed military documents, Egyptian pharaohs used them to confirm their obvious deity.

But a signature dear to my heart is young in comparison with these. And it was a grudge signature. Under duress, even.

English kings before 1215 were an omnipotent lot. They could do anything they liked, however they liked, and if you didn’t approve execution was a common consequence.

But John had not been a great example of an all-powerful monarch. He had crippled his subjects through raised taxes, he had waged some sorry apologies for wars: and he had picked fights with the Pope.

And his Barons, those of his Lords who were most powerful and moneyed, were getting edgy.

Good form at the time was to find an alternative potential monarch and back him to win. But the Barons had a problem.

There simply was no-one they thought suitable. Arthur of Brittany had all the obvious credentials, until he was disappeared in some very suspect circumstances. If John’s henchmen had had concrete boots at their disposal I feel sure he would have been equipped with these.

Prince Louis of France’s claim was tenuous at best, and at any rate the Barons had been at war with the French for the previous thirty years. One doesn’t simply negotiate truces and invite one’s enemy to take one’s throne.

The only option left was to make a silk purse out of a sow’s ear. They sent in the heavies, storming the walled city of London. The people of London decided the Barons were right; and rather than making the Barons’ men storm the walls, they opened the gates.

Whereupon the Barons simply forced John to put his name to a whole new way of operating. At Runnymede meadow, on June 15, 1215, he agreed to a document which limited his own power and guaranteed that no free man could be punished, except through the law of the land.

The great seal of the realm was added to the document: a powerful sign that the King had been here.

From those as base as Caliban to those with motives as pure as Ariel, everyone has a signature of some kind. The dog is the ridiculous, those wonderful Prisoners of war sublime.

And somewhere in between the two lies a King’s seal which guaranteed my basic rights eight hundred years ago.