The ship was launched in 1920 as Tyrrhenia by William Beardmore and Company of Glasgow on the River Clyde for Anchor Line, a subsidiary of Cunard. She was the sister ship of RMS Cameronia that Beardmore's had built for the same customer the previous year. Tyrrhenia was 16,243 gross register tons, long and could carry 2,200 passengers in three classes. She made her maiden voyage, Glasgow – Quebec City – Montreal, on 19 June 1922.