Complex sentence: He became widely known for his use of pigeons to fly his intelligence reports to England that were contained in a small tube using 3m thin paper whereon he complied detailed sketches of enemy lines with up to 5,000 words of explanation.
Split into simpler sentences: He became widely known for his use of pigeons to carry his intelligence reports to England. His missives were contained in a small tube using 3m thin paper, whereon he complied detailed sketches of enemy lines with up to 5,000 words of explanation.