Probability density function of the occurrence of the 11-year-average SN for 100 random realisations of the SN reconstructions (grey histogram). Panel a: Best-fit double Gaussian (μ₁ = 3.3, σ₁ = 3.6; μ₂ = 68, σ₂ = 51; red) and individual Gaussians (dashed blue). Panel b: Distributions of cycles that are defined to be part of a grand solar minimum (807–722 BC and 408–334 BC; see Table 1; blue) and the remaining cycles (orange).