Princess Irmelin

Irmelin is an opera written by Frederick Delius in 1890-92.  Before you nod off to sleep, here is the synopsis courtesy of the publisher and the wonderfully peaceful prelude is found below.
Princess Irmelin sits gazing out of the window of her room in the royal castle. Her maid chides her with ignoring knights close at hand whilst longing for a dream lover. None of the real ones interest Irmelin, but her father has insisted that she marry within six months. A servant announces the King, who introduces three suitor knights, the first old, the second fair, the third grasping. Irmelin turns them all down. The second act opens in a swampy thicket where the swineherd Nils is minding the pigs of the robber Rolf. In reality a prince, Nils regrets having been lured away from the silver stream he was following by the fatal forest flowers that have led him to his current state of subservience. Rolf calls him back to his castle, where his men are carousing. Nils refuses to sing for them, and announces his intention to leave, despite the attractions of Rolf’s women. The morning finds him back in the forest, where he once more follows the silver stream. Back at Irmelin’s castle, six months have passed and the betrothal of the unwilling princess is taking place. Nils enters and starts at the sight of Irmelin. She in turn is transfixed by him. He sings and plays for the assembled company. The king and his guests go hunting, leaving Irmelin behind. She calls Nils to her, and they agree to meet at midnight in the garden, where they sing of their happiness before disappearing into the forest together at dawn.

His publisher was Boosey and Hawkes who also put out a line of musical instruments for students.  I was looking at their website because, so it seems almost 6 decades ago I started playing clarinet and my instrument was made by them and I found something that came with that instrument in my keepsakes.At the end of the first year I played a solo on it "Long Long Ago" actually and those music books are what I found - Easy Steps to the Band and the Golden Book of Songs.