The strange ring around the sun which appeared over Leamington on Tuesday afternoon was simply a striking example of an optical phenomenon which has puzzled since the days of ancient Egypt.

Reader Steve Dixon sent us these pictures of a sun dog, or parhelion, at 1.45pm.

Unperturbed, he said: "The fact that this happened in the middle of the day is quite rare."

Sundogs are an atmospheric phenomenon associated with the reflection or refraction of sunlight by small ice crystals in clouds.

They can take a variety of forms, from halos to 'smudges' on the sky and be blindingly bright white circles or beautifully subtle red curves. Often, two can be seen at once.

In a world of instantaneous data from the Metrological Office, such appearances cause us little worry and only some of the old wonder.

But it wasn't always so.

The prelude to the Battle of Mortimer's Cross in 1461 is supposed to have involved the appearance of a complete parahelion with three "suns". The Yorkists took them to represent Edward of York, George of Clarence and Richard of Gloucester and their impending victory.

Among other notable historical accounts of parhelia, Shackleton's ill-fated polar expedition of 1912 was played out beneath "mock suns and green sunsets, and showers of jewel-colored ice crystals".

But by then the phenomenon was old hat.

Sundogs in fact appear in the writings of the ancient Egyptians, in Aristotle ("most commonly at sunrise or sunset, more rarely in the middle of the day") and in Cicero's On the Republic.

There an example was "mentioned in the senate" by those "neither few nor unworthy of credit, so that there is more reason for investigation than incredulity".

If that seems a down to Earth and sensible suggestion, it is worth contrasting with events in Stockholm nearly 1,500 years later.

For two hours on the morning of April 20, 1535, the skies over the city were filled with white circles and arcs crossing the sky.

The phenomenon quickly resulted in rumours of God's forthcoming revenge on King Gustav Vasa (1496-1560) for having introduced Protestantism during the 1520s.

So tetchy did the monarch get about it that when a painting documenting the event was put before him, those who commissioned the work were lucky to escape capital punishment.