 In citing this poem in his second union "Tractatus", Hume explicitly references both the Lion of Judah (associated with the Davidic Kingdom), and the Lion of Scotland, linking both with the "Lion of the North" prophecy of Paul Grebner; with a simple heraldic code, he also indicated the expansionism of the new kingdom, desiring the removal of the tressure bordering the Scottish lion rampant (harking back to the time of James III of Scotland).The "Lusus Poetici" (1605) were ultimately incorporated in Arthur Johnston's "Deliciæ Poetarum Scotorum" (1637).When Henry Frederick, Prince of Wales died, Hume wrote a memorial tribute entitled "Henrici Principis Justa", and in 1617 he welcomed the king back to Scotland in his "Regi suo Gratulatio."