Before there were umbrellas, there were trees. When people wanted shade from the sun or shelter from the rain, what did they do? They went and sat under a tree. Okay, so trees are less portable, but even if they weren't, you would probably be less likely to leave them on the bus by mistake.
The ancient Egyptians get a lot of credit for inventing the umbrella. Now they had a plenty of original ideas - pyramids and hieroglyphics and such like. But umbrellas (from ombra, the Latin word for shade)? A circular canopy radiating from a central stem? Remind you of anything that grows in the desert? It's a complete ripoff of the palm tree, obviously.
The Chinese first used the umbrella to keep rain off. It became an indicator of class, with servants carrying huge, ornate umbrellas over the heads of their masters. But its practical uses were soon superseded by the symbolic in parts of Africa and Asia, where it was used in ceremonies to signify the protection of state or deity.
The first Londoners to carry umbrellas, in the 1700s, were jeered by cab drivers worried that the new contraption would cost the trade. By the mid 1800s, well-to-do European ladies wouldn't be seen wet without an umbrella and when the sun was out they would carry a parasol to keep their skin fashionably pale. Even into the 20th century, the brolly - sported by City gents, golfers, John Steed of the Avengers and Mary Poppins - continued to signify a certain kind of upper-middle-class Englishness.
But umbrellas are not the valued possessions they once were. Furled up and forgotten, they litter lost property departments or lie, broken-spoked or blown out of shape, on rain-soaked pavements.
But there are certain times of the year - Wimbledon fortnight is one of them - when we are reminded of the unwritten law of umbrellas - if you don't take one out with you, it will rain. And when it rains there are two kinds of people - the umbrella-haves and the have-nots.
Indeed, the plight of the umbrella-less was never better expressed than by 19th-century judge Lord Bowen when he wrote:
"The rain it raineth on the just And also on the unjust fella But chiefly on the just, because The unjust has the just's umbrella."