- 1911: He went to study English at Liverpool University.
- 1914: Saunders enlisted voluntarily in the King’s Liverpool Regiment.
- 1915: He became a Lieutenant. He was sent to France that summer.
- 1920: He was appointed to his first job as an organiser of a scheme to develop rural libraries in Vale of Glamorgan.
- 1922: He became a lecturer in the Department of Welsh at University College, Swansea, and wrote his first Welsh-language play, 'Gwaed yr Uchelwyr' (Noble Blood).
- 1925: The political party Plaid Cymru is founded.
- 1931: He stood as a Plaid Cymru candidate at the General Election.
- 1935: He campaigned to halt the development of a Bombing School in the Llŷn Peninsula.
- 1936: Saunders, D. J. Williams and Lewis Valentine set fire to workers' huts on the site of the proposed 'Bombing School' and were arrested but released.
- 1937: The three were found guilty and were sentenced to nine months in Wormwood Scrubs prison.
- 1962: His radio lecture ‘Tynged yr Iaith’ (The Fate of the Language) was broadcast.
‘Mr Lewis has already given proof of his desire and ability to safeguard the interests of the Welsh people. We recall the invaluable work he performed, while still on the staff of one of the constituent Colleges, as a member of the Committee appointed by the University to further the claims of Wales to juster treatment by the B.B.C.’ – Welsh University Election 1943: Letter of Support to Mr. Saunders Lewis, p. 1 – https://viewer.library.wales/5150024#?cv=49