  We present a comprehensive multi-frequency study of the HBL 1ES 1959+650
using data from various facilities during the period 2016-2017, including X-ray
data from {\it AstroSat} and {\it Swift} during the historically high X-ray
flux state of the source observed until February 2021. The unprecedented
quality of X-ray data from high cadence monitoring with the {\it AstroSat}
during 2016-2017 enables us to establish a detailed description of X-ray flares
in 1ES 1959+650. The synchrotron peak shifts significantly between different
flux states, in a manner consistent with a geometric (changing Doppler factor)
interpretation. A time-dependent leptonic diffusive-shock-acceleration and
radiation transfer model is used to reproduce the spectral energy distributions
(SEDs) and X-ray light curves, to provide insight into the particle
acceleration during the major activity periods observed in 2016 and 2017. The
extensive data of {\it Swift}-XRT from December 2015 to February 2021 (Exp. =
411.3 ks) reveals a positive correlation between flux and peak position.
