No, they are not by the famous Cato the Elder of the Roman Republic, but the sayings of Cato were enormously famous and influential in the Middle Ages. They were probably composed sometime in the third or fourth century A.D., and you can learn more about them in this Wikipedia article. You can find the text online at The Latin Library; there's also a bilingual Latin-English version online. The Latin text in the widget follows that of Duff's Minor Latin Poets, online at the Internet Archive.