Can you supply historical notes on this madrigal by Thomas Weelkes?

  Since Robin Hood
    by Thomas Weelkes (c.1575-1623)
  
  |: Since Robin Hood, Maid Marian,
  And Little John are gone-a,
  The hobby horse was quite forgot,
  When Kemp did dance alone-a. :|
  
  |: He did labour / After the tabor,
  For to dance / Then into France,
    (for to dance then into France.)
  He took pains / To skip, (to skip,)
    to skip it in hope of gains, of gains.
  He will trip it, trip it, trip it on the toe,
  Diddle diddle diddle doe, (diddle diddle diddle doe.) :|
  

Source: The Oxford Book of English Madrigals, ed. Philip Ledger; Oxford University Press, 1978.

In particular, I'd like to know:
(1) Who is the Kemp referred to? The morris dancer Wil[l] Kemp?
(2) What is the historical context? What events does Weelkes refer to?
(3) When was the song written, or in which collection of pieces was it first published?