The 210 degreesC thermoluminescence (TL) peak of quartz, extracted from brick fragments of Somero sacristy (Finland), which were partly elements of construction, were used for the measurement of archaeological dose for the purpose of dating. The annual gamma dose-rate with cosmic component and beta dose rate of bricks were measured using two types of TLD detectors (AL(2)O(3)-C) inserted in situ and in laboratory, respectively, The improvements in the precision of the TL measurements, components of annual dose assessment are described, and the results of TL age determination are discussed and compared with the archaeologically expected age.