‘He is not my friend,’ I answered shortly. Nicholas reddened, and I continued more civilly, ‘Greening does not sound like such a man.’

‘No, indeed.’ Nicholas added, ‘The constable looked overworked.’

‘Yes. In some ways London is a well-policed city. The constables and watchmen look out for violence, and violations of the curfew. If a few taverns open after hours they wink at it, so long as the inn keepers do not let customers get violent.’ I looked at Nicholas and raised my eyebrows. His own tavern sword fight had become an item of gossip round Lincoln’s Inn, to my discomfort. He reddened further.

I went on, ‘The constables check that people obey the sumptuary laws regarding the clothes that may be worn by men of each station, though again they wink at minor infringements. And they run informers to report on crime and religious misdemeanours. But when it comes to investigating a murder requiring a long-term, detailed investigation, they have not the resources, as Fletcher said.’

‘I confess I do not fully understand about the different types of radical,’ Nicholas said. ‘Sacramentarians and Lollards and Anabaptists, what are the differences?’

‘That is something it is as well to know in London. But lower your voice,’ I said quietly. ‘Open discussion of these matters is dangerous. Sacramentarians believe the bread and wine are not transformed into the body and blood of Christ during the Mass, which properly should be regarded only as a remembrance of Christ’s sacrifice. By law, to express that belief is heresy. In most of Europe such opinion is new, but in England a man called John Wycliffe propounded similar doctrines more than a century ago. Those who followed him, the Lollards, were persecuted, but Lollardy has lived on here and there, in small secret groups. The Lollards were delighted, of course, by the King’s break with Rome.’

‘And the Anabaptists?’

They were one of the religious sects that sprang up in Germany twenty years ago. They believe in going back to the practices of the earliest Christians; they are sacramentarians, but they also believe that the baptism of children is invalid, that only adults who have come to knowledge of Christ can be baptized. Hence “Anabaptists”. But also, and most dangerously, they share the belief of the earliest Christians that social distinctions between men should be abolished and all goods held in common.’

Nicholas looked astonished. ‘Surely the early Christians did not believe that?’

I inclined my head. ‘Looking at the Scriptures, there is a good argument they did.’

He frowned. ‘I heard the Anabaptists took over a city in Germany and ran it according to their beliefs, and by the end blood was running in the streets.’ He shook his head. ‘Man cannot do without authority, which is why God has ordained princes to rule over him.’