O Wondrous Sight! O Vision Fair!

Another translation have "O wondrous sight!" instead of "O wondrous type!", such as found in United Methodist Hymnal number 258. It has another stanza (not found in oremus.org) right after the first stanza, as below:

From age to age the tale declares
how with the three disciples there
where Moses and Elijah meet,
the Lord holds converse high and sweet.

Refer to http://www.hymnsite.com/lyrics/umh258.sht for more information [including naming the Latin source as Sarum Breviary], and audio using piano or organ or bell.