How did Gottlob Frege contribute to logicism?

Gottlob Frege was a foundational figure in logicism, a school of thought in the philosophy of mathematics that posits all of mathematics can be derived from or reduced to pure logical laws.12

Frege’s contribution began with his development of a rigorous system of symbolic logic, notably presented in his 1879 work, Begriffsschrift. This work introduced a sophisticated use of quantifiers and predicates, establishing the basis for what is now known as first-order predicate logic.13

Following this, Frege articulated his logicist program, arguing that mathematical concepts—such as numbers—do not require independent definitions but can be defined through logical concepts alone. He detailed these views in works like The Foundations of Arithmetic and his magnum opus, The Basic Laws of Arithmetic. Although his specific intensional approach and unique notation faced criticism and were later challenged by Russell's paradox, his painstaking rigor and foundational research profoundly influenced later logicians, including Bertrand Russell and David Hilbert.213