Due to precession, what aspect of the Sun's path no longer aligns with the ancient assignments?

The constellation that holds the Sun on the Spring Equinox today versus two millennia ago

Precession dictates that the Earth's wobbling axis causes the celestial coordinates corresponding to specific dates to change over long periods. This means that the specific celestial longitude the Sun occupies on the date of the Spring Equinox—the location that was historically assigned to a particular constellation like Aries two thousand years ago—now corresponds to a different constellation boundary as defined by the modern IAU map. The physical path (ecliptic) is stable, but the labels (constellation names) applied to fixed longitudes along that path drift relative to the Earth's rotational orientation over millennia.