  We have been monitoring, at high cadence, the photometric and spectroscopic
evolution of VES 263 following the discovery in 2018 of a brightening labeled
as event Gaia-18azl. VES 263 is so far a neglected emission-line object
discovered in the 1960s on objective prism plates, tentatively classified as a
semi-regular AGB cool giant by automated analysis of ASASSN lightcurves. We
have discovered that VES 263 is a bonafide massive pre-Main Sequence object
(~12 Msun), of the Herbig AeBe type. It is located at 1.68+/-0.07 kpc distance,
within the Cyg OB2 star-forming region, and it is highly reddened
(E(B-V)=1.80+/-0.05) by interstellar extinction. In quiescence, the spectral
energy distribution is dominated by the 20,000 K photospheric emission from the
central B1II star, and at wavelenghts >=6 micron by emission from circumstellar
warm dust (Tdust up to 400 K). The 2018-19 eruption was caused by a marked
brightening of the accretion disk around the B1II star as traced by the
evolution with time of the integrated flux and the double-peaked profile of
emission lines. At the peak of the eruption, the disk has a bulk temperature of
~7500 K and a luminosity L>=860 Lsun, corresponding to a mass accretion rate
>=1.1x10(-5) Msun/yr. Spectroscopic signature of possible bipolar jets (at -700
and +700 km/s) of variable intensity are found. We have reconstructed from
Harvard, Moscow and Sonneberg photographic plates the photometric history of
VES 263 from 1896 to 1995, showing through 1953-1969 a state much brighter than
current eruption.
