Alghough David McK. Williams was indeed born in Wales, he was brought to Denver, Colorado before the age of one, so any qualification of his hymntunes as "Welsh" seems far-fetched! They are fine, sturdy tunes of course--just not Welsh. Probably mostly written while he was Organist at St. Bartholomew's in New York City. Some were specifically for the 1940 hymnal. (One was written to be included in the 1982 hymnal, published after his death.) I am the music director at the church in Denver where Williams became organist in 1900--at the age of 13! (It's still a tiny congregation.)