Beard The Lion In His Den Meaning

(idiomatic) To confront an adversary in his or her own environment

Example: 1808, Walter Scott, Marmion, Canto VI, st. 14:
  And darest thou then
  To beard the lion in his den,
  The Douglas in his hall?
1840, Thomas Pringle and Josiah Conder, Narrative of a residence in South Africa‎, page 45:
  George and John Rennie, and James Ekron, a servant of my father’s, announced their determination to march in and beard the lion in his den, provided three of the Mulattoes, who were superior marksmen, would support them.
1936, The Bankers magazine, Volume 132‎, page 307:
  Duty called me to beard the lion in his den; and though no Daniel, I took on the job without fear and trembling…