Alongside the emergence of theological conversations concerning correct sexual behaviour in marriage came conversations around whether marriage could be ended. The concept of the indissolubility (sacramentum) of Christian marriage is one that was developed rather late in Christian thought. It was not until Augustine and his response to the Jovinian controversy of the late fourth century that a fully coherent narrative and theology was constructed. In Augustine's writings, this sacramentum manifests itself in the impossibility of remarriage (for either men and women) after divorce because of the creation of ‘one flesh’ from two bodies at the point of marriage. To Augustine, and those who followed, a marriage between two Christians was more than simply a legal formality for the production of children, but marked the formation of an unchanging and immutable spiritual bond between two souls. The separation of this bond was considered to be theologically impossible, a concept which leads to an extremely hard line on the possibility of separation or divorce in Christian thought, a line which corresponds neatly with the broad pattern visible in the secular legal texts. The primary example of this line of thought is found in Isidore’s tract on church offices sandwiched between his expositions on the correct role of married women. He states that a man and wife cannot be separated because the Church and Christ – the epitome of a spiritual marriage – cannot be separated. He then gives a litany of presumably common but obviously frivolous reasons for marital disquiet or separation, including sterility, deformity, old age, illness, body odour, intoxication, irritability, immorality, luxuriousness, foolishness, gluttony, a quarrelsome nature, an abusive nature or wandering, and states that they are invalid. In common with both the New Testament and the secular laws he does allow female adultery as the sole extenuating circumstance under which a marriage could be ended, although unusually he also includes situations in which the wife is merely suspected of adultery. The notion that female adultery destroyed the spiritual bond between man and wife is common in the patristic age. Apart from this very slight deviation, Isidore's discussion is merely a condensed version of Augustine's theology, drawing on very commonly cited biblical quotes as justification.