I don't think it's right that \rm in math mode means \mathrm. Or, at least, plain.tex assumes that \rm gives text roman, e.g. from plain.tex (line 1067), \def\arctan{\mathop{\rm arctan}\nolimits} Thus, the following example has the "arctan" text in Euler math. This problem doesn't occur with Latin Modern or with Palatino, because somehow (I'm not quite sure how) they have \rm inside math meaning text roman. \usetypescriptfile[euler] \definetypeface [mainface] [rm] [serif] [pagella][default] \definetypeface [mainface] [ss] [sans] [modern] [default] [rscale=1.075] \definetypeface [mainface] [tt] [mono] [dejavu] [default] [rscale=0.9] \definetypeface [mainface] [mm] [math] [pagellaovereuler][default] \appendtoks \rm \to \everymathematics \setupmathematics[lcgreek=normal, ucgreek=normal] \setupbodyfont[mainface] \starttext \startformula \arctan x \stopformula \stoptext