I was wondering over the TeX programming language syntax. Is there a known reason why Knuth chose the backslash notation we all love and fear? It seams to me that most other contemporary languages (C, Prolog, Smalltalk, SQL) use syntaxes more alike as well as more easily read- and writeable, i.e. there was already common lexical scanning techniques around to use, not to end up with a cryptic notation. Is the reason commonly known?