  Using information on geomagnetic activity, sunspot numbers and cosmogenic
isotopes, supported by historic eclipse images and in conjunction with models,
it has been possible to reconstruct annual means of solar wind speed and number
density and heliospheric magnetic field (HMF) intensity since 1611, when
telescopic observations of sunspots began. These models are developed and tuned
using data recorded by near-Earth interplanetary spacecraft and by solar
magnetograms over the past 53 years. In this paper, we use these
reconstructions to quantify power input into the magnetosphere over the past
400 years. For each year, both the annual mean power input is computed and its
distribution in daily means. This is possible because the distribution of daily
values divided by the annual mean is shown to maintain the same lognormal form
with a constant variance. This study is another important step towards the
development of a physics-based, long-term climatology of space weather
conditions.
