Complex sentence: George Frederick Ruxton (born 24 July 1821, died 29 August 1848) was a British explorer and travel writer who observed the expansion of America in the 1840s during the period when the US government was pursuing its policy of manifest destiny.
Split into simpler sentences: George Frederick Ruxton (born 24 July 1821, died 29 August 1848) was a British explorer and travel writer. He observed the expansion of the USA in the 1840s during the period when the US government was pursuing its policy of manifest destiny.