Gaius was a member of the Plinia "gens:" the Insubric root "Plina" still persists, with rhotacism, in the local surname "Prina". He did not take his father's cognomen, Celer, but assumed his own, Secundus. As his adopted son took the same cognomen, Pliny founded a branch, the Plinii Secundi. The family was prosperous; Pliny the Younger's combined inherited estates made him so wealthy that he could found a school and a library, endow a fund to feed the women and children of Como, and own multiple estates around Rome and Lake Como, as well as enrich some of his friends as a personal favor. No earlier instances of the Plinii are known.