It is generally agreed that the eleventh century marked a transition of major importance in the history of Christianity in western Europe. A number of developments contributed to this changed situation. The threats of invasion of western Europe from Scandinavia or Moorish Spain receded. The power of the eastern empire, based at Constantinople, went into decline. Until the arrival of the Black Death in the late 1320s, western Europe was relatively free of the lethal pandemics that had wreaked havoc in earlier times – such as the “Plague of Justinian” in the sixth and seventh centuries.
By the end of the eleventh century, sustained population growth in the cities of northern Italy had laid the foundation for early forms of capitalism and a more sophisticated urban culture. The papacy reasserted its independence and authority, and became a major reli- gious and political influence throughout western Europe. The reforms introduced by popes during this period deserve closer attention, and we shall consider them further in what follows.