I have a special reason for coming to this particular church. It feels cool within those thick stone walls. The noise of the lawn mower working away outside cannot penetrate the stone or the windows.

I contemplate the frescoes on one of the walls. The skeleton of Death is chasing a human being, smiling wryly and wielding his scythe. The man is terrified of Death, which always comes untimely. In this ancient place I am faced with pictures of the Black Death, the Plague. Time stands still, but the reality of past time is present even so.

It occurs to me that amongst all these images of Gotland peasants, I can see Aida. A black face among the medieval farmers from Tingstäde and Roma. Solidarity among men and women is as much present in horror as it is in joy.

Among the people portrayed are her mother, her brothers and her sisters. Death pursues them all down the ages. The images frozen onto the walls of the medieval church are in some ways a moving picture. The figures come running towards me, gliding through arrested time.

Then it was the Plague, now it is Aids. Then it was bacteria, now it is a virus. But death is never visible. Whence does the illness come? Where do the sores come from, what causes the emaciation?

Why should bacteria and viruses be so small that they cannot be seen? Why should they have this unfair advantage?

I sit in a pew in the dark interior and reflect. When did I first hear about this insidious and mysterious illness that seemed at first only to affect gay men on the west coast of America?

I cannot remember.

I have searched my memory and gone through newspapers from the early 1980s to see if there might be a headline I recognise, that could help me to fix a specific date. At certain times in my life I have kept detailed and seriously intended diaries, but they have not been able to help me either. I cannot find a moment that I can point to with any degree of certainty and say: this is when I realised that something momentous was happening. A new epidemic illness had put mankind under threat. Nor do I recall any conversations with friends about the illness, definitely not before 1985 or 1986.

Perhaps it was the sight of the actor Rock Hudson on a stretcher in Paris. I remember that distinctly. There were photographs on the front pages of all the main newspapers. It was immediately clear that the man who – not least together with Doris Day – had made so many films over so many years in which he had played a husband in an idealised and hence dishonest American marriage, was in fact homosexual. What had he been thinking of as he wandered around in his striped pyjamas, always immaculately ironed, Doris Day at his side, also smiling non-stop and fussing around?

Now he was dying, not at all old. His last journey to Paris in a chartered aeroplane was reminiscent of the handicapped faithful who tried to recover their health by going on a pilgrimage to a shrine of the Madonna. A last desperate attempt to keep death at bay by trying a new form of treatment that was said to be available in France.

I remember reading that he slept twenty-three hours a day. The one hour he was awake he devoted to telling stories about his life. I shuddered.

That news photograph of Rock Hudson is among my earliest intimations of Aids. At that time we had not yet been exposed to the mass of pictures and documentation. All the photographs from Africa, with anonymous men and women, emaciated bodies, sunken eyes, people without hope, without strength.

I also recall a young African quoted in a newspaper: "Must we die because we are in love?"

But the first decisive impression? I am pretty sure it was Rock Hudson. It was as if a sculpture guaranteed unbreakable had nevertheless shattered. And yet I am not absolutely sure.

On the other hand, I can say precisely when Aids became real for me, when I myself became frightened of the illness, terrified that I had been infected.

I knew, of course, how one became infected. And, yes, I had friends who were doctors and they assured me that there were no short cuts that the infection could take to attack me. Nevertheless, the fear was there. I know it is a fear that I shared and still share with many people.

It is easy to lie about this. Easy to boast that one has never experienced any trace of the irrational fear of being infected, despite the fact that common sense tells you that you have not been exposed to any risks. That is how it has always been. People ten or so years older than I am have stories to tell about a similarly needless fear of having been stricken with syphilis. They will tell you about the Wasserman test they had to take before being accepted as a blood donor, and that it was a good way of establishing that one did not in fact have a syphilis bomb ticking away in one's body. I remember as a teenager being scared stiff by stories about gonorrhoea. I don't think I've spoken to a single person in connection with venereal disease who hasn't felt a cold shiver down the spine at least once in their lives.

But the fear of HIV and Aids? I recall it very clearly. There was a period in the 1980s when the fear was especially widespread. All kinds of horror stories were circulating in the mass media. There was an account of how a passenger suffering from Aids was not allowed to board an American flight from China. The captain refused to allow him on board. There were those who argued that people infected should be branded, or tattooed in the groin. Or why not herd them together and maroon them on remote islands, there to await their deaths?

There are moments when the frescoes in the Gotland churches seem to be speaking directly to us, right now. Not only addressing us, but speaking about us, and that we are part of their story.

It was also in the mid-1980s that people started looking for scapegoats. Politicians with extreme views started fishing in muddy waters, but they were not the only ones looking for scapegoats, a lot of "ordinary" people were also carried away by the fear. Homosexuals were branded the guilty party, the ones who were spreading the disease. Just as in the past it was the Jews who had been blamed for spreading the deadly plague by infecting people's wells.

So it was the homosexuals who should all be branded, especially if they were black men. All black men seeking asylum in Europe should be subjected to HIV tests. Those infected should be turned away.

When the history of Aids in the 1980s comes to be written, a lot of ugly truths will emerge with full and frightening force.

In our part of the world at least, the absolute terror is no longer with us. There are nevertheless some people still who maintain that the Aids epidemic is the wages of sin. The scapegoats exist, be they asylum seekers, homosexual men or Russian prostitutes.