Final answer:
Agnes de Courtney does not match the descriptions provided and seems to be confused with other individuals. No historical record under this name correlates with the details given.
Step-by-step explanation:
There appears to be confusion regarding the identity of Agnes de Courtney. The question seems to conflate different figures by the description provided. Based on the material specified, none of the Agnes descriptions match historically with Agnes de Courtney. The closest person of renown who shares the name is from the medieval period, associated with the nobility of the Crusader states. However, given the references in the materials, there's mention of Agnes Macphail, the first female member of the Canadian House of Commons, a separate historical figure of significance and unrelated to Agnes de Courtney. Additionally, Agnes Warner was a known nurse during the Great War, again a different person. The description quoted regarding a woman of uncertain temper seems more akin to a fictional character than any historical Agnes de Courtney.