Long-term fluctuations of solar activity during the last thousand years

Long-term variations of solar activity during the last thousand years were derived from historical observations (by the naked eye) of large sunspots and from records of auroras at latitudes < 55°. The results shown in Figure 1 indicate very good agreement as regards the occurrence of maxima and minima of all three indices (sunspots, auroras, ¹⁴C), and even between secondary fluctuations of the ¹⁴C-curve, which were usually neglected in the presentation of the smoothed curve.