  We report on the results of the multiwavelength campaign carried out after
the discovery of the INTEGRAL transient IGR J17329-2731. The optical data
collected with the SOAR telescope allowed us to identify the donor star in this
system as a late M giant at a distance of 2.7$^{+3.4}_{-1.2}$ kpc. The data
collected quasi-simultaneously with XMM-Newton and NuSTAR showed the presence
of a modulation with a period of 6680$\pm$3 s in the X-ray light curves of the
source. This unveils that the compact object hosted in this system is a slowly
rotating neutron star. The broadband X-ray spectrum showed the presence of a
strong absorption ($\gg$10$^{23}$ cm$^{-2}$) and prominent emission lines at
6.4 keV, and 7.1 keV. These features are usually found in wind-fed systems, in
which the emission lines result from the fluorescence of the X-rays from the
accreting compact object on the surrounding stellar wind. The presence of a
strong absorption line around $\sim$21 keV in the NuSTAR spectrum suggests a
cyclotron origin, thus allowing us to estimate the neutron star magnetic field
as $\sim$2.4$\times$10$^{12}$ G. All evidence thus suggests IGR J17329-2731 is
a symbiotic X-ray binary. As no X-ray emission was ever observed from the
location of IGR J17329-2731 by INTEGRAL (or other X-ray facilities) during the
past 15 yr in orbit and considering that symbiotic X-ray binaries are known to
be variable but persistent X-ray sources, we concluded that INTEGRAL caught the
first detectable X-ray emission from IGR J17329-2731 when the source shined as
a symbiotic X-ray binary. The Swift/XRT monitoring performed up to $\sim$3
months after the discovery of the source, showed that it maintained a
relatively stable X-ray flux and spectral properties.
