From lcrchurch.org/toptenhymns.htm

7. Beautiful Savior
(#518, Lutheran Book of Worship)
Click on the Piano to listen to the Hymn


Hymn #7 in the LCR Top 10 countdown dates back to 1677, when the words were included a German Jesuit hymnal or songbook called the Munster Gesangbuch. But despite its Catholic origins, it is now firmly identified with American Lutherans. In fact, there are dozens of Lutheran churches named after this hymn.

The words were translated from German in 1873 and published in the Lutheran Sunday-School Book by Joseph A. Seiss, a prominent Lutheran pastor, author, and a founder of the General Council, one of the first efforts to unify the many Lutheran church bodies in the U.S. Another translation of the hymn – "Fairest Lord Jesus" – is used by many other Protestant churches. The fourth verse is the same in both versions.

The tune comes from a folk tune from Silesia, now part of southern Poland but formerly part of Austria and then Germany. It's called the "Crusader's Hymn" because it was erroneously thought to date from the time of the Crusades.

No irony that I can see given the actual origins of the hymn and the fact that most know it only as either "Beautiful Savior" or "Fairest Lord Jesus."