Complex sentence: After a year studying medieval confession, he joined the magazine Index on Censorship, before proceeding to The Times as a trainee, rising swiftly to become Assistant Editor at the age of 26.
Split into simpler sentences: After a year studying medieval confession, he joined the magazine "Index on Censorship", before proceeding to "The Times" as a trainee. There he rose swiftly to become Assistant Editor at the age of 26.