He was further appointed the coadjutor bishop of Chilaw in 1968.
He became coadjutor bishop of Niagara in 2007 and its diocesan a year later.
Until recent times, there was the possibility of a coadjutor bishop not having the right of succession.
He asked the Holy See to name a coadjutor bishop to assist him.
He served as Coadjutor Bishop from 1902 to 1911.
He was elected coadjutor bishop in 1959 and diocesan in 1966.
However, Alemany wished to return to missionary work and requested a coadjutor bishop.
He requested a coadjutor bishop be named to assist him and then succeed him after his death.
Plessis had also furthered his own career, becoming coadjutor bishop of Quebec.
In 1958, he was appointed a coadjutor (assistant) bishop in the diocese.