Henceforth, St. Elmo, the sole study of my life shall be to forget my alphabet.

It's been my sole study.

I regret indeed that I have not time to make infancy and the development of its powers my sole study.

I often said to myself, 'My sole study has been to merit well of mankind; why do I fear them?'

In the year 1257, he bought by chance an old book for two florins, which soon became the sole study and object of his life.