I just realized the pattern in a somewhat unexpected behavior in a typescript. It defines several instances of Adobe Caslon (with or without certain ligatures, oldstyle, proportional numbers etc.). I want typewriter and math from Latin Modern. In the end, the typefaces are defined: \starttypescript [Caslonpnum] \definetypeface [MyCaslonpnum] [rm] [serif] [caslonpnum] [default] [encoding=\typescripttwo] \definetypeface [MyCaslonpnum] [tt] [mono] [modern] [default] [encoding=\typescripttwo] \stoptypescript Here's the catch: as soon as I add a definition for a math font: \definetypeface [MyCaslonpnum] [mm] [math] [modern] [default] [encoding=\typescripttwo] oldstyle figures will always be taken from the math font. If I delete this line from the typescript, I get the oldstyle figures from the font defined as [OldStyle]. Looks like a bug to me. Or am I misunderstanding something? Thomas