Will coincide with the entry of transiting Pluto into the tropical sign of Aquarius. The original zodiacal longitude of Pluto at our country's founding was 27 degrees of Capricorn, and add the three-plus degrees to correct for equinoctial precession since our nation's founding, and you cross over into zero degrees of Aquarius, since the tropical zodiac is the one affected by equinoctial precession.
This ingress of transiting Pluto into the tropical sign of Aquarius is not the same as the much discussed dawn of the Age of Aquarius. Strictly speaking, the Age of Aquarius will down when the Vernal EQuinox Point of the tropical zodiac precesses, or moves backwards, from zero degrees of Pisces in the sidereal (star-based) zodiac (we are currently in the precessional age of Pisces) into 29 degrees of sidereal Aquarius. Since the Vernal Equinox Point of the tropical zodiac is currently at about 6 degrees of Pisces, and the Vernal EQuinox Point precesses, or moves backwards, by one degree every seventy-two years, the actual ingress of the Vernal Equinox Point back into sidereal Aquarius won't happen for another 400 years or so.
Using this calculus, if we add one degree to the Vernal Equinox Point for every 72 years back in time, the entry of the VEP into sideral Pisces from sidereal Aries coincides pretty much with the ascension of the Roman emperor Constantine to the throne, and his making Christianity the establishment religion of the Roman Empire. With that crucial milestone, the religion of Jesus and his fishermen had triumphed, and the Piscean Age of Faith had begun.