He changed it during DS9’s run (from '93 to '99) – I remember being surprised to see the change in the credits. So it was definitely prior to 9-11.
According to IMDB, “Was originally ‘Siddig El Fadil’, but has changed his name to ‘Alexander Siddig’ because (as reported by him at Star Trek conventions) nobody could pronounce ‘El Fadil’.”
And a counter-spy in MI-5 he’s been getting a lot of work – which is good, he’s a fine actor, but the role of Bashir was mostly terrible – and really DS9 is probably my Trek of choice.
Siddig had a English mother (the sister of Malcolm McDowell, no less) and sent a great deal of his life in Britain. “Alexander” may have been a name he went by in English-speaking contexts.
The name change appeared in the DS9 credits at the beginning of the 4th season. IIRC, Sid (as we fans call him regardless) explained his choice of Alexander because it was what his mother wanted to name him.
And on the ‘behind the scenes’ stuff on the DS9 disks the other cast members refer to him as ‘Sid’.
I remember a small flap when he changed his credited name. He said he wanted something that would open more doors for him and a few Arab groups told him they were disappointed because they’d been glad to see such an arab name on the credits of a prominent show.
I’m almost ashamed to admit it, but I was a member of his fan club at the time the name change occurred. He didn’t give an explanation then, but the change did cause a lot of remark - mostly because the dog he owned then was named Alexander. (Imagine a lot of Indiana Jones riffs - ‘You are named after the DOG?’ - as only SF geeks can do them.)
He’s also been heard to remark that he picked the name as a tribute to his Uncle Malcolm’s role in ‘A Clockwork Orange’.
This is all old info. I’ve been out of Trek fandom a long, long time.
I actually asked him about it at a convention. He said that, yes, he did want to have a name that was easier to pronounce. But he had another motivation and that was that he was annoyed at how much money Paramount was making off his name and image (particularly with regard to action figures) and what a small cut he got of the take, so he thought he’d change his name just to annoy them. He had a secret plan to change his name once a year, but he didn’t follow through with it.
He also emphasized that he changed only his stage name, not his legal name.
I have a feeling that there is more behind it. It seemed to me that there is some back-story about his parents’ split up. His father’s family were very important in Sudan – I think his uncle was president or something – and his mom had to go through a lot to get him back to England; I’m guessing there might have been a big tussle over custody and such. This is all specualtion though.