Complex sentence: The square used to be called "Riddarholmstorget", but was in the mid- 19th century renamed "Birger Jarls Torg" after Birger Jarl, traditionally attributed as the founder of Stockholm, and a statue of him was erected on the square in 1854.
Split into simpler sentences: The square used to be called "Riddarholmstorget", but was in the mid- 19th century renamed "Birger Jarls Torg" after Birger Jarl, traditionally attributed as the founder of Stockholm. A statue of him was erected on the square in 1854.