In spring 2018, the sediment core TRI1 (38°33'0.61" N, 21°35'20.76" E) was retrieved from 50m water depth in the central eastern part of Lake Trichonida, the largest Greek lake, using a high-precision wire-operated piston corer system (Usinger system). The here presented TRI1 master core sequence covers 438 cm (sedimentary units 9 - 19). The concentrations of total nitrogen (TN), total organic carbon (TOC), and total inorganic carbon (TIC) were determined on 21 dried, grinded, and homogenized samples through combustion in an elemental analyzer (Euro EA, Elementanalyzer). The core sequence covers the last 2600 years and was analysed to reconstruct ecosystem and landscape changes as well as palaeoclimatic fluctuations in SW Greece.