Are national anthems secular hymns?
Many national anthems are religious hymns.
No. They are national anthems. Hymns are songs of praise to God. Some national anthems include references to a god, but they are essentially songs of praise to a country.
God Save the King (or Queen) is very clearly a hymn. It's a prayer set to music. And it barely mentions the country, with one reference to reigning over "us" and one to defending "our laws" being as close as it gets. It's a call for divine support for the person of the monarch.
It's a secular hymn at best. The original lyrics (published in 1745):
God save great
George our king,
Long live our noble king,
God save the king.
Send him victorious,
Happy and glorious,
Long to reign over us,
God save the king!
Today's standard version:
Long live our noble Queen!
God save the Queen!
Send her victorious,
Happy and glorious,
Long to reign over us:
God save the Queen!
Thy choicest gifts in store,
On her be pleased to pour;
Long may she reign:
May she defend our laws,
And ever give us cause,
To sing with heart and voice,
God save the Queen!
It is not a religious hymn. It's an anthem. While it contains an intercessional request addressed to God, the essential ingredient of a religious hymn is missing.
A
hymn is a type of
song, usually
religious and partially coincident with
devotional song,
specifically written for the purpose of adoration or prayer, and typically addressed to a deity or deities, or to a prominent figure or
personification.
The word hymn derives from
Greek ὕμνος (
hymnos), which
means "a song of praise".
National anthems that praise a country, without reference to the seeking of divine support for it, tend to be those written in the twentieth century; Older anthems are usually hymns.
The very etymology of the word 'anthem' reflects this: Originally from Latin (probably via French) meaning a verse-response song, by the C14th it meant "a composition (usually from Scripture) set to sacred music" and by the end of the C16th "song of praise or gladness". It came to be used in reference to the English national song, which as I point out above is itself a hymn, and was then extended in meaning to refer to the national hymns of other countries, and later still to national songs that might not be hymns.
Thanks for outlining how anthems have changed over the centuries. It looks like on their way from being "a composition (usually from Scripture) set to sacred music" they have morphed into "song of praise or gladness". In the case of God Save the King (or Queen) the target of praise is not God. It's the noble King or Queen.
(All emphases are added by me.)