Use it when emphasizing that events occur simultaneously within a specific historical or chronological timeframe. The coronations of the English and Spanish monarchs were contemporaneous events.
Pro Tip 2/3
Academic Texts
It's often used in academic or formal writing to discuss events or phenomena in history, science, or art. Picasso's earlier works were contemporaneous with the cubism movement's peak.
Pro Tip 3/3
Not Interchangeable
'Contemporaneous' is not always interchangeable with 'contemporary' despite their similarity. Though contemporaneous, their political ideologies were not contemporary in terms of popularity.