Galleys shall break the crimson seas
seeking delights for you;
Okay, so apparently this king commands a fleet of warships, because he's going to send them all over the world, tasked with the mission of finding beautiful things to delight his wife.
Do ships really "break" the seas? Not really; it's a figure of speech. It brings to mind the prow of a ship, crashing through the waves.
And how about the seas—aren't they usually thought of as blue?
Howard could have said: "Galleys shall break the blue seas . . . ", but that would have been what the reader expects, and therefore a bit less intriguing. (It would also have spoiled the rhythm of the words).
"Crimson seas" makes us use our imaginations. What does the phrase bring to your mind? I picture the way that the sea looks at dawn or dusk.
With silks and silvery fountain gleams
I will weave a world that glows and seems
The king is saying that he's going to "weave a world." That doesn't make sense, at least not literally. People weave blankets, rugs, and fabrics; they don't weave worlds. What he probably means is that he will "create" a world for her, which is also figure of speech, because I don't think he can create an entire planet. But you get the idea.
And what kind of thread is he going to put in his loom? Silk thread, for starters. But he's also going to weave in "threads" of silvery, gleaming water from a fountain. That sounds kind of hard to do.
A shimmering mist of rainbow dreams,
scarlet and white and blue.
In these lines we get a description of the world that the king is planning to weave. From the previous line, we know it's going to "glow". And now we're learning it will also seem like "a shimmering mist of rainbow dreams". Wow. I'm picturing unicorns and rainbows.
Furthermore, the king tells us that the dominant colors of this dreamy world will be scarlet, white, and blue. I wonder why he chose these colors?