There were three sister ships. Titanic, sank on its maiden voyage in April 1912, having struck an iceberg (like we don't all know this!). Britannic, launched just before WWI began in 1914, was pressed into service as a hospital ship and struck a mine in the Aegean Sea in November 1916. Olympic -- the flagship -- was in service from 1911 to 1935 and was retired and scrapped. If this is a valid plaque, it would pretty well have to have been made in early 1912. I can't imagine they would have continued to make them after the disaster.