Cathcart ownership of the lands of Sundrum and Auchincruive is recalled in a verse foretelling the demise of the family's fortunes:Sundrum shall sinkAuchincruive shal faeAnd the name o' CathcartShall in time wear awae[2]Alan, 4th Lord Cathcart signed the Glasgow band of the west country barons to support Mary, Queen of Scots and Lord Darnley during the Chaseabout Raid on 5 September 1565.
[4] On 3 January 1579, James VI of Scotland wrote from Stirling Castle to Lord Cathcart, commending him for his service and the expenses he had made against rebels.
Now that Cathcart had joined royal domestic service as a Master of the Household he would be given a yearly fee of 1,000 merks.
[5] Around this time, Cathcart completed the sale of lands and the site of the House of Bogtoun, or Bogton Castle, between Holmwood and Muirend, to John Blair of Blair and his wife Grissel Sempill (Cathcart's cousin).
His father is sometime identified as a "Lord Sudram" (Sundrum), mentioned as a leader of the Scottish army before the battle of Solway Moss.