Balthasar Thames?

Maybe it's not so much a name as a title that's passed down. A little research uncovers a number of different Balthasar Thames', each one playing a pivotal role in some major event or another, all across the planes.

In a hub city attached to a Multiverse full of myriad fecund races in which there are a relatively small number of useful names, it would not at all be surprising to have Sigil be experienced with frequent collisions in the namespace. Heck, on our own world I share first and last names with two much more famous artists, a painter and an author.

The role of coincidence in the history of the Cage is probably one that greatly interests the Transcendent Order, the Fraternity, and the Xaositects, and to a lesser extent probably the Sign of One and the Sensates. Imagine what would have happened in Sigil if Factol Vartus Timlin hadn't keyed his vault door to a jaunty tune from an obscure Prime, which happened to be the homeworld of an enterprising thief who liked to whistle, or if Pentar hadn't shared a name with twelve other people in Xaos, in their case a loose fraternity of extremely annoying soldiers from a Roman-inflected world that named their kids by number("the fifth one"). Xaositects say that such coincidences make any attempt to find patterns in history or predictions meaningless; on the other hand, many Guvners subscribe to the "trend" theory of history, which claims that such coincidences are on the whole minor ripples in events which would take place anyway. Admittedly, it's hard to imagine Pentar as anything other than a raving Sinker.

(It has struck me for some time that "Erin Montgomery" sounds very much like a name from our own world, as compared to names like Hashkar, Sarin and Skall. The Factol's Manifesto has her being raised in a tiny village on the Outlands, but nothing strictly about her life before age 10 -- and when she left Tir Na Og, she spent her time wandering, not the Outer Planes, but the Prime Material -- the notes for which "disappeared from the Manifesto before printing." Looking for a way home, perhaps?)