Umlaut - history

Umlaut - Wikipedia: "Originally, umlaut was denoted in written German by adding an e to the affected vowel, either after the vowel or, in small form, above it. (In medieval German manuscripts, other digraphs could also be written using superscripts: in bluome ('flower'), for example, the "o" was frequently placed above the "u".)

In blackletter handwriting as used in German manuscripts of the later Middle Ages, and also in many printed texts of the early modern period, the superscript "e" still had a form which would be recognisable to us as an . However, in the forms of handwriting which emerged in the early modern period (of which Sütterlin is the latest and best known example), the letter had two strong vertical lines, and the superscript looked like two tiny strokes. Gradually these strokes were reduced to dots, and as early as the 16th century we find this handwritten convention being transferred sporadically to printed texts too"