Complex sentence: Robert Stanley Weir,, (1856-11-15--1926-08-20) was a Montreal, Quebec judge and poet most famous for writing the English lyrics to "O Canada", the national anthem of Canada.
Split into simpler sentences: Robert Stanley Weir,, (1856-11-15--1926-08-20) was a Canadian judge and poet. He is most famous for writing the lyrics to "O Canada", the national anthem of Canada.