The solar activity-radiocarbon-climate relationship of the Little Ice Age, a period of low solar activity, will be compared with that of the Medieval Warm Epoch, a period of low solar activity. Additionally, USSR data of Kocharov, which suggested a 20% fluctuation in C14 content of tree rings with an 18 year period (and no 11 year cycle) during the Maunder minimum, will be evaluated. Computer modelling will also be performed to test the stationality of the C14 periodicity over the 10 millennium record, to examine periods not yet studied but which appear in the power spectra, and to determine if the relationships between the C14 record and delta O18 signals from the Greenland ice cores are also evident in the delta O18 record of Antarctic ice cores. The work will include high-precision C14 analysis using liquid scintillation spectrometry of single-year tree-ring samples for the time periods in question. ***