Which mathematician is known for the concept of mathematical rigor and formal proofs?

Euclid is recognized for his significant contributions to mathematics, particularly in the development of geometric principles and the formalized approach to mathematical proofs. His work, especially in "The Elements," laid down a systematic framework for geometry that established definitions, postulates, and logical deductions that are fundamental to the concept of mathematical rigor. This work not only influenced the study of mathematics but also the way mathematical proofs are constructed, emphasizing clarity and logical sequence. This emphasis on a logical structure and proof in mathematics is what distinguishes Euclid’s contributions as pivotal in establishing rigor in the field.