What is Pliny the Elder’s claim to fame and who was Pliny the Younger?

Pliny the Elder (A.D. 23-79) was an encyclopedist of the Roman Empire whose reputation as an expert on scientific matters endured until the Middle Ages.

Pliny was also known as Gaius Plinius Secundus.

His adopted son, Pliny the Younger (c. A.D. 61–c. A.D. 113), was a lawyer and administrator known mainly for the large collection of private letters he left behind.