My library has 2 editions of Bethlehem & they seem to be fairly widely held. Neither have music. Our copies are available through interlibrary loan & other libraries' copies should be, check with your local library. The edition kytrad mentions is Bethlehem only. The other ed. has more: Bethlehem : a nativity play ; the Pageant of Our lady & other poems / by Laurence Housman. London : Macmillan, 1902. 85 p. The other poems are 8 Christmas songs.

Preface
All the songs of the 'Nativity Play' together with the whole of the 'Pageant of Our Lady' and the 'Christmas Songs,' which are here printed, were designed to be set to music by my friend, Mr. Joseph Moorat. Standing thus separate from their context, their appeal to the reader is necessarily incomplete.

The World is Old is sung by the Shepherds after a choral introduction as the curtain opens at the start of the play.