[4] From 1905, Clarke was educated at Alexandra College, Dublin, matriculating at Queen's University Belfast (QUB) in 1910 taking a first-class honours degree in history.
[1] She filled the vacancy left by F. M. Powicke at QUB from 1916 to 1919, before returning to Oxford to take a position as a history tutor at Somerville College.
Her first publication was a paper on the Irish parliament during the reign of Edward II, which was read to the Royal Historical Society in December 1925.
Around this time she started her research into Richard II, from which she produced the article "The Lancastrian faction and the wonderful parliament", read at the International Historical Congress in Oslo in 1928.
[1] Working with Vivian Hunter Galbraith, Clarke published an edition of the Dieulacres Chronicle in 1930 on the subject of the deposition of Richard II.