Calderwood's Altar of Damascus is considered by many to be one of the major classics of Reformation thought regarding worship and church government. "The 'Altare,' or Altar of Damascus (a title founded on 2 Kings 16: 10-11), is Calderwood's masterpiece, and contains an elaborate examination of the constitution and ceremonies of the Church of England (and thus Prelacy and the English Popish ceremonies which the most faithful Reformers have always condemned--RB).

The original of the Latin work was a tract in English, published in 1621. It is said that King James, on reading this looked melancholy, and being asked the cause pointed to the formidable treatise. 'Let not that trouble your majesty,' said the courtier, 'I shall soon answer it.' 'Answer what man' replied the King, 'there is nothing there but Scripture, reason, and the fathers'" (Johnston, Treasury of the Scottish Covenant, p. 284).

"The 'Altare Damascenum' is beyond comparison the most learned and elaborate work ever written on the subject, embracing the whole controversy between the English and Scottish divines as to government, discipline, and worship" (Thomas M'Crie as cited in Treasury of the Scottish Covenant, p. 284). This volume is the English "tract" (of 222 pages) referenced above.