бытность
жен. в бытность мою студентом ≈ in my student days в бытность его в Риме ≈ during his stay in Rome, in his Rome days в бытность ≈ when, during someone's stay
ж. : в мою ~
в Москве when I was staying/living in
Moscow, during my stay in
Moscow;
в мою ~ студентом in my student days.
Большой англо-русский и русско-английский словарь.
2001.