Trade Winds Contest!

Everybody is so glad that the Trade Winds are finally here. After the rainy season it has been Hotter than July, to borrow from Stevie. Of course, that is only hearsay as it is always a toasty 98.6 in my hot tub made for one. But anyway, everybody seems more relaxed now that the winter breezes have finally arrived. As some of you may know, these are the same winds that brought Ferdinand Magellan to the islands. I am of course referring to the Spaniard who was given credit for being the first to circumnavigate the globe (he didn't quite make it, he was killed in the Philippines). Now for the contest. Here is your question Karsten2008 readers: In 1521, Magellan landed in the Mariana Islands, what did he name the islands, and why? If you can answer this simple two parter and leave the answer in a comment, you qualify to be put in the running for a live deer courtesy of the Kagman Mobil station (Must be over 18 but less than 19, a resident of Outer Mongolia, and have 6 toes on your left foot. Other rules and resrictions may apply, please contact Karsten 2008 for a full list of rules and details)