He tells me that it's a well known (to some) poem by Goethe (a contemporary of Beethoven). Stuart regularly plays a piano version each May if he remembers: "it's good to mark the start of summer."
https://youtu.be/To3Td-V7FU8
Mailied
Poem by Johann Wolfgang von Goethe. Music by Beethoven
How brightly nature
How brightly nature
Shines this morning!
What radiant sun!
How the fields sing!
The buds burst forth
From each green frond!
A thousand bushes
Resound with song!
And joy and wonder
Streams from each breast.
Oh Earth! Oh Sun!
Oh joy without rest!
Loveliest of loves!
Loveliest of loves!
Fair and golden,
Like morning clouds
On the mountain.
You renew each field
With veils of mist.
And your morning dew
Leaves each field blest
.
Oh how I cherish
You, sweetest maid!
How your eyes shine bright
Where love can’t fade.
As morning larks love
To sing and fly,
As springtime flowers
Greet the blue sky,
So do I love you
With all my heart!
The one who inspires
Youth, joy and art;
A mood for new songs,
Dancing lively.
Oh be so happy
As you love me!
And here's a sung version from 1956 - Fritz Wunderlich and Rolf Reinhard:
