Lawrence Stone believed that from the time of the Reformation, which led to a narrowing of the grounds for annulment, until just prior to the Restoration, when private separation agreements became possible, the bonds of marriage were harder to break than at any other time in English history. Later historians have disagreed with Stone about the precise contours of marriage law and practice during these decades. R. H. Helmholz, for example, has questioned the ease with which the pre-Reformation church granted annulments, while Martin Ingram remains sceptical of Stone's assumptions about the prevalence of desertions after the Reformation. Nevertheless, few historians dispute the legal, ecclesiastical and social strength of the institution of marriage between the mid-sixteenth and mid-seventeenth centuries. Elsewhere in Europe, the Protestant reforms that removed marriage from its sacramental pedestal also ushered in the possibility of divorce, but in England divorce in the modern sense – the legal dissolution of a valid marriage allowing parties to remarry – remained unobtainable for most couples until 1857.