Since the classic paper of A. A. Griffith in 1920, questions have been asked about the variability of the strength of glass fibers as a function of composition and processing conditions. While Griffith apparently found that the strength of soda-lime-silica fibers increased as their diameter decreased, he also found that quite large-diameter silica fibers had strengths of the order of 6.9 GPa (1 X 106 psi). Since that time, almost all investigators have found very similar strength values for silica regardless of the fiber diameter, raw material or conditions of formation. The history of the strength of fused silica fibers and the effect of various coatings on the strength, fatigue and aging are reviewed in this paper.