TrueType was known during its development stage, first by the codename "Bass" and later on by the codename "Royal".[2] The system was developed and eventually released as TrueType with the launch of Mac System 7 in May 1991. The initial TrueType outline fonts, four-weight families of Times Roman, Helvetica, Courier,[3] and the pi font "Symbol" replicated the original PostScript fonts of the Apple LaserWriter. Apple also replaced some of their bitmap fonts used by the graphical user-interface of previous Macintosh System versions (including Geneva, Monaco and New York) with scalable TrueType outline-fonts.