I have noticed that in older English texts the terms Dutch and German are often used interchangeably, with Dutch often being used to describe German being predominant in the 17th century, though there seems to be a change by the 18th century towards the word German. One text, I found from the 16th century does already make the distinction between "high Dutch" and "lowe Dutch" with the former being spoken in Vienna. Below is a page from William Camden's 1614 Remaines of a Greater Worke, Concerning Britaine describing the Spanish, French and Dutch (German).