The ancient oak of Guernica, says Laborde in his account of Biscay, is a most venerable natural monument. Ferdinand and Isabella, in the year 1476, after hearing mass in the church of Santa Maria de la Antigua, repaired to this tree, under which they swore to the Biscayans to maintain their "fueros" (privileges). What other interest belongs to it in the minds of this people will appear from the following.