In the fourteenth century what are called _water-marks_ came into use, together with the invention of linen paper. Some simple device indicating the city or province where the paper was made was woven with fine wire into the bottom of the sieve, and this mark was impressed upon the paper, like that of the other (parallel) wires of the sieve. A double-headed eagle, a vase, a letter or a bull's head are among the earliest paper-marks which occur in manuscripts and books of the fifteenth century[244]. In later times, during the sixteenth century, each manufacturer adopted his own mark[245]; and then still more recently the year-date has been added[246]. _Evidence of date._ These paper-marks in some cases afford useful evidence as to the origin and date of a manuscript or printed book; but too much reliance should not be placed on such evidence, since paper often remained for a long time in stock, and the productions of one manufactory were frequently exported for use by the scribes and printers of more than one distant country[247]. Paper of Oriental make has no water-mark, but the earliest linen-paper of the fourteenth century made in Christian Europe always has a water-mark of some kind, very clearly visible. _Earliest cotton paper._ _The dates of paper manufacture._ The earliest paper appears to have been made in China at a date even before the Christian Era. Its manufacture was next extended in Syria, and especially to Damascus[248]. This early paper was made of the cotton-plant, the "tree-wool" of Herodotus. Hence it was called _charta bombycina_ or _Damascena_, or, from its silky texture, _charta serica_. Paper of this class, almost as beautiful in texture as vellum, is still made in the East and used for the fine illuminated manuscripts of India, Persia and other Moslem countries. _Arab MSS. on paper._ Many Arab manuscripts written on cotton-paper of as early a date as the ninth century still exist. The Moslem conquerors of Spain and Sicily introduced the manufacture of this _charta bombycina_ into western Europe, and to some small extent it was used for Greek and Latin manuscripts during the tenth and eleventh centuries. It was, however, rarely used in Christian Europe till the thirteenth century. _Wool-paper._ At first cotton only was used in the manufacture of paper, but gradually a mixture first of wool and then of flax or linen was introduced. Peter, who was Abbot of Cluny from 1122 to 1150, in his treatise _Adversus Judaeos_ mentions manuscripts written on wool-paper, made "ex rasuris veterum pannorum." _Linen paper._ In the fourteenth century linen-paper began to be made; at first mixed with wool, and then of pure linen. This fourteenth century paper is distinguishable by its stoutness, its close texture, and its thick wire-marks; the water-mark being especially clear and transparent. Paper was frequently used for official documents, charters and the like before it came into use for manuscript books[249].