I have had many opportunities to talk to Cossa over the years about the feverish nature of his relations with women and, essentially, our debate all came down to this. I would point out to him – for instance, after he became pope – that love was God's, and that the proper place for fornication and sodomy, with their burden of sin, was marriage; they had not been designed for constant promiscuous pleasure. I reasoned with him within the tenets of his own religion (which was not mine) that every golden moment of the Christian existence had to measure up to the profound philosophical preconceptions and prejudices of its founding fathers. Using the trick of his sweet smile which even though I fully understood its use, I could not resist – he would answer me that, because religious and secular law were practically one tissue, the 'morality' of sex had become imbedded in religious law. Having created-guilt and blamed it on Adam and Eve, the founding fathers of the Church saw that the easiest way to remind people of their guilt was by putting restraints on all human pleasures. He told me, patiently, that the `morality' of sex was, therefore, an important factor in social control. He admired the founding fathers for having had the genius to separate sexual relationships from all other human relationships, then to give sex a permanent stain of inner-felt unholiness. But, he said, God or nature has a far stronger influence over us than the ambitions of clergymen, and God insists that the most, important act of our lives is to reproduce ourselves. This desire to do the right thing in God's eyes is so strong in us – certainly in me, he said, it may be different with you Germans – that it cannot be overcome by slanted doctrines from covetous minds.

He became angry with Bernaba during the first year he was chancellor because she said he should allow her to send women to him – he most certainly had received carnally other wives and daughters of Bologna- and that he should stay away from Castelleto Street because it just didn't look right for a man of his dignity, an archdeacon as well as chancellor, and therefore a promising prelate of the Church, to be seen by students entering and leaving a whorehouse. They got into a hot argument over that. Bernaba was a woman of strong character and she recognized no difference between herself and Cossa – or anyone else. Cossa told her to run her whores and keep her advice to herself, so she called. him as stupid donkey and he told Palo to take her outside and beat her. Palo started to get her, but I stepped on his feet, and when he fell down I stumbled over him somehow and tell on his head with my knees, somewhat heavily. Bernaba enjoyed it but it made Cossa even angrier.

`Listen,' I told him, 'Bernaba is one of the oldest friends we have. We don't want anyone – particularly Palo – getting the idea that he can beat her.' I stared at him until he got the point. At last he smiled and said, `I'm sorry. I just lost my temper. It's been a long day.'

She ran across the room, put her arms around him and gave him a big kiss. `Just stay out of Castelleto Street,' she told him. `I'll send you all the women you can handle. You're the chancellor. You have to, give a good impression.'

They were pals again,; but, some years later, when I married Bernaba, she wanted our marriage to be kept secret. `Listen, Franco,' she said tome, `Cossa thinks you are only alive to serve him. He would break all the furniture if we told him.'

`My God, Bernaba,' I said. `How can I keep a secret from Cossa?'

`There is one easy way to do it, Franco. Keep remembering that he is capable of sending me to his father to be sold in the slave market at Bari. He is a nice man. But why should he know?'

I must explain how I can write down this history of my friends or autobiography, depending on how you see it. It would be too easy to allow my own life to dominate this narrative. But this is Cossa's story. I have the feeling that Church history isn't going to deal well with Cossa, but we have to remember that, for all his gestures of action, Cossa was a passive fatalist who allowed things to happen to him. Villains are never like that. Villains always know what they want and they, move to get it. There were villains on every side of Baldassare Cossa and not all of them inside the Church.

I have known Cosimo di Medici almost as long as I have known Cossa. Cosimo was a few years younger than Cossa, Boniface I was ten years older than Cossa, and I was senior to all of them. Cosimo is a banker so, he doesn't talk much unless he needs something, or its plotting something, but he has told me plenty. After I became a cardinal everybody wanted to tell me everything they knew. It's a kind of bragging on their part. The ones who knew the most about things which should be buried deep in the ground were Bernaba's friend Decima Manovale and her four daughters. The daughters told Manovale and Manovale told Bernaba.

Bernaba was my wife for over twenty years. She is dead now. Bernaba was in a business which gave her the keys to a lot of closets. Some things she didn't tell me until the year she died. She wasn't concealing anything. Whatever I asked her, she told me. After most of the people in our lives were gone, I knew everything she knew about them before I wrote this book.

For example, Decima Manovale. When Cosimo's father began to take an interest in Cossa, Manovale told Bernaba about it. That is so long ago that, at the time, the Medici was only the third, ranking bank in Florence after the Bardi and the Albizzi. The Bardi were ruined by loans they made to the English crown. The Albizzi favoured the rich. So the Medici had no choice but to go after the business of the middle classes and the poor, and that wasn't easy. Cosimo's father was the most ambitious man in Europe. His son was just a son when he started in the bank, and he couldn't really make much of himself until his father died… By that time, they were the biggest bank in the world. The old man was called Giovanni di Bicci di Medici. He worked every corner. He operated farms, manufactured silk, traded with, Europe; Russia and Islam, which was against the Church law – but his ruthless ambition was some day to become the banker for the Church.

Cosimo di Medici told Manovale's daughter Maria Giovanna that his father's obsession with Church banking dated from the day when he found out from some country.bankers in Cahors that the papal treasury at Avignon had 18,000,000 gold florins and 7,000,000 more worth of plate and jewellery on deposit with them. Gold florins were the most desirable currency in Europe. One gold florin was worth three and a half English pounds and old man Medici probably considered all of it to be family money because it was named after the republic of Florence.

Cosimo di Medici's father's one overwhelming desire was to attract the Church's banking away from the different Sienese, Roman, Venetian and foreign banks into one central depository, of all Church income and capital controlled by him,, because he believed that those other banks didn't understand how to use the power of such an opportunity.

The Church was the great industry of Christendom. Its bankable deposits flowed not only from the Vatican but also from the holy sees and religious orders, and from the obediences of the princes who were dependent upon the Church and that meant all of them. The old man used to get furious (Cosimo told Manovale who told Bernaba who told me) because nobody seemed; o realize that the Church income and capital should be centrally organized.

Giovanni di Bicci di Medici had another, invisible, advantage. The papal tax-collecting organization naturally favoured Italian employees, for this established and maintained the predominance of Italian banks throughout Europe. Even business in and around the North Sea and the Baltic was largely financed by them. He kept repeating to his son that if one bank had everything the Church deposited. any pope could be made content, even happy, and the bank therefore could, prosper beyond anything any banker (except Giovanni di Bicci di Medici)' had ever dreamed of. With a few happy popes leaning on every see, every prince, every religious order, to bank with one single bank's branches – which would be conveniently located everywhere, – a banker could have a really flourishing business…