I've been checking some recent work on the Last Millennium Climate Reconstructions — specifically the PMIP4 and CMIP6 datasets. These models show that while there were natural climate fluctuations, the long-term trend over the past few thousand years has been relatively stable, with a slight warming trend in the last 1000 years, especially post-1850. The cooling claims often conflate short-term events like the Little Ice Age with long-term trends. The data doesn't support a consistent downward trend over millennia.