Complex sentence: The "Regimen" was contemporary with Secretum Secretorum, a health manual written by pseudo-Aristotle, but the "Regimen" was more popular, due to the easier to remember rhyming verse.
Split into simpler sentences: The "Regimen" was contemporary with Secretum Secretorum, a health manual written by pseudo-Aristotle. However, the "Regimen" was more popular, due to the easier to remember rhyming verse.