The twelfth century was an important period for the manufacture of the hand-made book. For most of the century, most books were made at and for monastic communities. This meant that, on the one hand, the numbers of books expanded as monasticism grew in popularity, and on the other, that books were made with great care, and an eye on their durability: monastic books were expected to last as long as their contents were relevant, that is potentially for ever. The average twelfth-century book is made of well-prepared parchment, strongly bound in wooden boards covered with skin, and written and decorated using material and techniques that resisted dislocation or fading.