The first change that occurs in a later stage of the hymn is that the phrase or clause, instead of being repeated exactly, is varied by a change of words, having a similar import. In short, we have the beginning of parallelism. There is parallelism in the poems of all early civilizations. It reaches its fullest development in an age of civilization, as we observe in the poems of the Bible.
Probably the oldest poetry we have is that of the Egyptians and the Babylonians, and there is no regular metre of any kind in these except parallelism. The works are all irregularly rhythmical and in many cases the lines are arranged like modern free verse, to call attention to this irregular rhythm.
Dr. James H. Breasted, speaking of the Pyramid Texts, in his _Religion and Thought in Ancient Egypt_, says: "Among the oldest literary fragments in the collection are the religious hymns and these exhibit an early poetic form, that of couplets displaying parallelism in arrangement of word, and thought--the form which is familiar to all in the Hebrew Psalms as 'parallelism of members.' It is carried back by its employment in the Pyramid Texts in the fourth millennium B.C., by far earlier than its appearance anywhere else. It is indeed the oldest of all literary forms known to us. Its use is not confined to the hymns mentioned, but appears also in other portions of the Pyramid Texts, where it is, however, not usually so highly developed."
All the poems of the Egyptians were written simply in rough, irregular lines of rhythmical prose. Read the famous _Song of the Harper_ where an epicurean life is praised; it is impassioned rhythmical prose. Take up the love poems, elegies, fairy tales and prayers of the ancient Egyptians. They have no device of metre, rhythm or rhyme. The only pattern is the parallelism. A few hymns are arranged in stanzas of ten lines with a break in the middle of each line, but no definite metrical laws existed for the lengths of lines or number of feet, so as to make a uniform rhythmical pattern of the composition.
The Egyptians wrote much of their poetry in parallelistic prose. If we do not know how they pronounced their vowels, we know enough of their literature to see that regularity of accents and equal numbers of syllables were not characteristic of their poetry.