While changing his name from Jones to Bowie might have been the first mask that Bowie put on, his first real transformation was into the character of Ziggy Stardust. Like most concept albums, the specifics of the plot and background of Ziggy Stardust and his backing band, The Spiders from Mars, are muddled. But David committed to this character so completely and thoroughly that when he finally did decide to kill it off (or retire it) it was big news that came as a shock even to the other musicians on-stage with him at the time.
The original gambit may have been little more than a way to get out of his own head – much as the Beatles adopted the Sgt. Pepper moniker. But this proved so successful that he continued it into the next album. At least sort of. Aladdin Sane is supposed to be it’s own story with its own character, but it really didn’t have the same impact and really just felt like an extension of the Ziggy Stardust character. The most memorable thing from Aladdin Sane is the facial make-up that Bowie wore on the cover and millions have imitated since.
However, Bowie was having a hard time coming up with new songs for his rock-star alien persona, so his next album was a covers album entitled Pin-Ups It featured many of the English bands that Bowie listened to growing up and influenced him, even if they were only a few years older than him. He was going to do a follow-up that featured American acts, but Pin-Ups ended up being such a disappointment that it never happened.
By this point Bowie was probably starting to feel as constrained by his Ziggy character as he once was by his own (fake) name. He was going to need to change things up again.