An especially popular version of the Tagelied was the Wächterlied, or watchman's song, in which a trusted watchman warns the knight to depart. This form was introduced into German use by Wolfram von Eschenbach.
The form of the Wechsel (alternating verses by the knight and the lady, but not addressed directly to each other, so not quite a dialogue as now understood) was introduced by Dietmar von Aist and Heinrich von Morungen.
Important motifs of the Tagelied are the depiction of daybreak, the warning to depart, the lament at parting and the lady's final permission to the knight to go (the urloup).
Particular exponents of the genre were among others Heinrich von Morungen, Wolfram von Eschenbach, Walther von der Vogelweide and later Oswald von Wolkenstein. Modern poets who have drawn on the tradition of the Tagelied include Rainer Maria Rilke, Ezra Pound and Peter Rühmkorf.
See also
Most of this article is based on that in the German Wikipedia