The WWP uses the principle of “reading order” to determine how to encode multi-line elements which are arranged horizontally across the page, e.g.:
12 November, 1665 I am, dear Sir,
The Cottage, Findlebury Very truly
Westmoreland And obediently yours
This is a situation which arises in many contexts; the most frequent are closers (as above), stage directions, and the various addenda to pamphlets or petitions.
The principle of “reading order” is that we encode each entire piece of text in the order in which it would normally be read, starting at the top of the page and reading (in general) from left to right, top to bottom. On the assumption that the reader reads each chunk of text as a unit, reading order operates at the element level, not at the line level, so we do not break up the individual textual chunks but encode them as entire units. Thus in the example above, we would encode the entire dateline as a unit, with internal line breaks, followed by the entire salute.