This book is doubly a labour of love. The editor, Ronald Rittgers, one of the most insightful, subtle and humane writers on early modern Christianity that we have, makes no bones about how deeply he has been drawn in by the text he edits for us here, and about his sense of connection with and obligation to its author. And the text itself, the ‘Pious meditations on the alas, most sorrowful bereavement of Johann Christoph Oelhafen’, almost all of it written in eleven months during 1619–20, is a wrenching glimpse into the spirit of a man almost broken by the death of his beloved wife, and into how over the year of his widowerhood he rebuilt himself. It is a remarkable text: there is nothing quite like it from the period. It deserves, and it has found, the most dedicated and sensitive of editors.

The text, which is mostly an inward-facing set of meditations, would not immediately tell you how remarkable a man Oelhafen (1574–1631) was. Coming from a prominent Nuremberg legal family, he proved brilliant enough to become the city council's legal counsel aged only twenty-five, before taking his doctorate: an unprecedented honour. He became an imperial count palatine, a bibliophile with a vast library and represented his city in the meetings of the Protestant Union in the run-up to the conflict we now call the Thirty Years’ War.

But more to the point: in around 1601 he married his second cousin Anna Maria Harsdörffer. He called her his AMICO – an acrostic of their joint initials, Anna Maria Iohan Christoph Oelhafen, but also of course Latin for friend, and, by Johann Christoph's telling, this certainly seems to have been an intimately companionate marriage. Seems: as Rittgers rightly points out, we never actually hear Anna Maria's own voice, so we only have one side of the story. When we read that she nearly died following complications from her twelfth pregnancy in 1617 (and lost the baby), and then that her thirteenth pregnancy in 1618 (this baby, too, died) broke her health so that she was dead three months after the birth … well, it is hard not to wonder if a more genuinely loving husband might perhaps have left her alone. But that is very likely my twenty-first-century prejudice talking. It would be completely normal for a seventeenth-century Lutheran woman to see marriage and childbearing as her vocation and to choose, with all clarity and courage, to pursue it to the end.

Johann Christoph's response to her death was to begin and keep a spiritual journal of his grief. It is intimate and inward, a very unusual glimpse deep inside Lutheran piety; it contains what is, as far as we know, the only verbatim representation of what an early modern Lutheran said in secret to a confessor (Johann Christoph includes a text which he says he read out to his confessor, barely a month after his AMICO's death). And yet it is also not private. The text, as Rittgers found it in the German National Museum in Nuremberg, is a well-presented formal manuscript, written not merely for his own self, but to be shared with his family, especially the eight children who survived their mother's death, and of course – above all – with his God. And it is the dialogue between his ruined grief and his steadfast Lutheran faith that makes this, not only a record of one man's pain, but a witness to the consolation he was able to find in his religion.

In some ways it bears comparison with its English counterpart three and a half centuries later, C. S. Lewis's A grief observed (London 1961). Lewis's account is more raw and less mannered, and he wrestles openly with doubt; and yet, he was also self-consciously writing (and editing) for publication as Oelhafen was not. And Oelhafen can be raw enough. ‘O living God and consoler of all the sad-hearted … you have torn away a piece of my heart.’ But that agonised prayer is closely based on a popular published prayer for a bereaved husband. I think there is no doubt Oelhafen meant every word of it: but a recurrent theme of his meditations is how he found consolation in and through the structures of Lutheran piety, its texts, its rites, its liturgical calendar and its sacraments. They were the scaffolding he used to rebuild himself. But he used it actively, assertively. ‘Open to me the door of your holy wounds’, he prayed in March 1619. ‘I will not stop pounding and knocking until you have mercy on me. I will not let up until you console my soul, bless me, and give me peace again.’

The largest number of his entries – especially as the year wears on – are in the form of poetry, often (as he notes) written to fit the tunes of popular Lutheran hymns, and mostly written as acrostics, spelling out, more often than not, variants of AMICO. Here Rittgers's outstanding facility as a translator shows its worth. Making an acrostic poem work in translation is tricky, and Rittgers only attempts it when he can do so without distorting the text; but he invariably and vividly conveys the heartfelt quality inhabiting these sometimes formal and formulaic verse structures. On his wedding anniversary, Oelhafen wrote an unusually long poem, in the form of a dialogue between himself and his AMICO, to be sung to a tune which he and she used to play together. If you can read it dry-eyed, you're made of sterner stuff than I am.

But he did, it seems, find a measure of the consolation he sought. As the year wears on, the meditations have less of the intense encounter with a ‘great and frightening God’ and more of the diary, recording his health issues, the fraught politics of the Bohemian revolt and his responses to the liturgical calendar as well as his ever-present undercurrent of grief. And then, in February 1620, just over a year after Anna Maria's death, he remarried, to the twice-widowed Catharina Pfinzing, whom he called his CICO and with whom he had one further child. As Rittgers says, it hardly fits with our romantic notions; but he was a prominent man, she was closely connected to the city elite, he needed a helpmeet and his eight children needed a mother. It was how things were done.

Writing a book of lamentations, however, was very much not how things were done in Lutheran Germany. This was a buttoned-up public culture which did not encourage displays of grief and in which lament was not an established pious or literary genre. We cannot of course know whether Oelhafen's quiet subversion of those norms made him, his marriage and his piety exceptional, or whether the feelings to which he gave voice could speak for his times. Nor does it really matter. ‘To have had you with me’, he wrote to his departed AMICO, ‘has been happiness enough.’ That Rittgers has enabled him to share some of that happiness and pain with us, four hundred years on, is its own gift.