  We present a reconstruction of total solar irradiance since 1610 to the
present based on variations of the surface distribution of the solar magnetic
field. The latter is calculated from the historical record of the Group sunspot
number using a simple but consistent physical model. Our model successfully
reproduces three independent data sets: total solar irradiance measurements
available since 1978, total photospheric magnetic flux from 1974 and the open
magnetic flux since 1868 (as empirically reconstructed from the geomagnetic
aa-index). The model predicts an increase in the total solar irradiance since
the Maunder Minimum of about 1.3 \rm{Wm$^{-2}$}.
