Roman and Italic Together
“Only a few systems of writing – Latin, Greek, Cyrillic, Armenian – have developed bicameral form [having both upper and lower case], but every script that is heavily used develops multiple styles, including some that are more brittle, segmented and precise, and some that are more cursive. After such contrasting forms establish themselves, they subdivide in turn. This has happened with the brittle and fluid forms of the Latin lower case, which are known as roman and italic. Latin script is unusual, however, in the intimate way it has come to exploit the difference between the two. Using one script for heads, another for text is common enough around the world. But mixing two such scripts like this, in the midst of a single-language sentence, is comparatively rare and was a late development even in Latin script.”
[Robert Bringhurst, The Solid Form of Language, 46]