It does not appear that the definite assigning of particular colours to particular days is of older date than Innocent III's time; but before him, and even as far back as the time of the fathers of the church, we find that the early Christians had symbolical associations with colours, which have formed the foundation on which the elaborate structure of later times was built. It is a matter of common knowledge that there are associations of sentiment and colour which are practically indissoluble. Black and sorrowful, white (or bright) and joyful, are synonymous terms, and similar expressions are universal. _White_, in the first ten centuries of Christianity, typified purity and truth. Saints, angels, and Our Lord are for that reason represented clothed in white. As we have seen, the earliest vestments were probably white; the newly-baptized wore white during the week after baptism, and the dead were shrouded in white; the latter, however, probably more for convenience than for any symbolic reason. _Red_, the colour of flame, was associated with ideas of warm, burning love. Our Lord is sometimes represented in red when performing works of mercy. _Green_, the colour of plants, was regarded as typifying life, and sacred or beatified persons are sometimes depicted as clothed in this colour in reference to their everlasting life. Lastly, _Violet_, which is formed by a mixture of red and black, was said to symbolize 'the union of love and pain in repentance.' It also typifies sorrow, without any reference to sin as its cause; thus the _Mater Dolorosa_ is occasionally represented in a violet robe.[100] Further than this we cannot go, and perhaps we have said too much. It is quite possible that these theories may have been put forward to account for phenomena which depended entirely on the taste and whim of the painters. It is well known that in the early ages of Christianity ideas of colour were vague, and yellow and green, dark blue and black, light blue and violet, were all regarded as being the same colour. Previous to the tenth century, it is quite true that coloured vestments are to be seen in mosaics and fresco-paintings; but the combinations of colours are such as to leave no doubt that they were simply adopted by the painter as convenient aids to distinguishing the various vestments from the surrounding background and from each other. Coming now to Innocent III, we find that he prescribes four liturgical colours, white, red, black and green. These were the principal or primary liturgical colours; but there are others, secondary to these, which were modifications in tint of the primaries. Thus, properly, red is the colour of _martyrs_, white the colour of virgins; but there is a secondary colour, saffron, for _confessors_, and the secondaries, rose and lily, are considered interchangeable with red and white.