。
It was Socrates who laid the foundations of logic.
Literal
Logic [possessive-の] foundation [object-を] made [cleft-のは] Socrates [copula-である].
A classic cleft construction: ~のは~だ ('the one who did X is Y'). This structure emphasizes the answer (Socrates) by placing it at the end. ~である is the formal copula. Historically, logic is more often attributed to Aristotle, but the sentence works as a grammar example.