Complex sentence: A successor, Father Uladzimir Tarasevich, was appointed in 1983, but, after his death in 1986, Father Alexander Nadson was appointed Apostolic Visitator, but not, at his request, raised to episcopal rank.
Split into simpler sentences: A successor, Father Uladzimir Tarasevich, was appointed in 1983. After his death in 1986, Father Alexander Nadson was appointed Apostolic Visitator, but not, at his own request, raised to episcopal rank.