Good Friday Morning!!
About that midsummer solstice thing. . .
I read somewhere that the change in kings, (Oak & Holly) signifies the change in the life of the sun. As in the winter, the new sun is born on Yule, after the old sun dies, Midsummer signifies 1) the longest day of the year (most amount of daylight), 2) the height of maturity of the sun (king), and the point when the king is considered to have reached maturity, and when he begins to age and die.
At least, I think that's how it went. Sorry for rambling on, and Happy Friday All!