In this illuminating study Danielle Park analyses two interrelated subjects: the papal protection of crusaders, initially granted to the crusaders themselves, then extended to their families and lands; and what she terms the ‘crusade regencies’ of wives and guardians who ruled in the absence of the crusaders. By viewing papal encyclicals through their impact on the ground, as it were, through chronicles, letters and charters, Park is able to relate the theoretical character of papal protection to the actual families and lands under protection. Her case studies deal primarily with French royal domain and the neighbouring counties of Flanders and Champagne, which supplied large numbers of crusaders in the twelfth century and for which relatively abundant sources survive. Her close reading of the primary sources within the context of recent historical scholarship makes this careful study required reading for anyone interested in the consequences of the crusades at home, a still understudied subject, and medieval regencies in general.

It was Urban ii who first extended the papal protection of crusaders and their personal possessions to their families and properties left at home during the First Crusade. That protection, Park argues, was as important to the recruitment of combatants as the promised remission of sins. She credits Eugenius iii and his Quantum praedecessores encyclical announcing the Second Crusade for formalising that protection of the ‘wives and children, goods and possessions’ of crusaders, and for making prelates responsible for its enforcement. By this reading, Alexander iii and Innocent iii did not so much innovate as continue what Urban and Eugenius had formulated.

Parks's case studies begin with Countesses Clemence of Flanders and Adela of Blois, who ruled their husbands’ lands during the First Crusade, although it is not clear how papal protection actually affected their rule. Better documentation is available for the royal regency during the Second Crusade, in the absence of both Louis vii and Queen Eleanor. Park speculates that Louis appointed Suger of Saint-Denis as his primary regent because he distrusted his mother Adela of Savoy, and makes a strong case for Suger acting only to preserve specific royal interests, not as the king's alter ego. More typical was Countess Sybil, who ruled Flanders twice during Count Thierry's absence overseas, on pilgrimage in 1138–9 and during the Second Crusade. In both cases Sybil was an active ruler, taking counsel with her husband's advisers but acting without formal constraint. Most striking was her appearance at the Council of Reims (1148), where Eugenius himself made an example of papal protection by deciding for her against the count of Hainaut, who had invaded her husband's lands.

Countess Marie of Champagne was another vigorous ruler of her husband's lands during his pilgrimage to Jerusalem in 1179–81. Although she solicited Alexander iii’s letter of protection – which he granted, he said, for the land of her husband ‘and for you and all that pertains to you’ – she is not known to have cited his protection in any of her acts. When her unmarried son, Count Henry ii, went on the Third Crusade, Marie returned to rule for him and continued for the next seven years in what might be called a co-lordship while he remained overseas. Her sister Alice, countess of Blois, also ruled for her husband and, after his death in Acre, for the next five years for her under-age son. Their half-brother King Philip ii, widowed shortly before the crusade, established a limited regency consisting of his mother, the dowager queen Adele, and his uncle Archbishop William of Reims. Park ends her case studies with the longest regency of all, by Countess Blanche of Champagne (1201–22) for her son, born days after the death of Count Thibaut iii as he was preparing for the Fourth Crusade. Although Blanche's regency was not strictly speaking a crusade regency, since papal protection ended with the death or return of a crusader, it makes a nice book-end to the regencies of the long twelfth century.

Park makes two major contributions to our understanding of the crusades. The first is in mapping the evolution of papal protection over the course of the twelfth century and demonstrating the critical role of Eugenius iii in its ultimate formulation. The second is showing how an important consequence of the crusades was the emergence of well-born women as active rulers in the absence of their husbands. That was possible, she argues, because women were already experienced in governing, and therefore amply qualified to serve as regents. Here she raises an issue of terminology. We ordinarily think of regents as royal officers or distinguished personages acting for under-age royal heirs, whereas ‘crusade regency’ shifts the meaning to rule for an absent husband. Since in most cases the regents or guardians were wives (occasionally a mother, brother or even a minor son), one might well conclude that a wife assumed her husband's rule as a matter of course, as a spousal right and responsibility, while continuing to control her dowry and dower property. That speaks to the nature of elite families in the twelfth century, which recent studies have shown to have been inherently conjugal. When a count of Blois, Champagne or Flanders accepted the risks of a crusade, he naturally would leave his lands and office in the hands of his closest relative, in most cases his wife. Park has made an important contribution in presenting regency, for a crusade or otherwise, as an integral part of the aristocratic family's experience, one that deserves far greater attention in all studies of medieval families.