  We investigate the formation and morphological evolution of the first
galaxies in the cosmic morning ($10 \gtrsim z \gtrsim 4$) using the Horizon Run
5 (HR5) simulation. For galaxies above the stellar mass $M_{\star, {\rm min}} =
2\times 10^9\,M_{\odot}$, we classify them into disk, spheroid, and irregular
types according to their asymmetry and stellar mass morphology. We find that
about 2/3 of the galaxies have a S\'{e}rsic index $< 1.5$, reflecting the
dominance of disk-type morphology in the cosmic morning. The rest are evenly
distributed as incidental and transient irregulars or spheroids. These
fractions are roughly independent of redshift and stellar mass up to
$\sim10^{10}\,M_{\odot}$. Almost all the first galaxies with $M_{\star}>
M_{\star, {\rm min}}$ at $z>4$ form at initial peaks of the matter density
field. Large-scale structures in the universe emerge and grow like cosmic
rhizomes as the underlying matter density fluctuations grow and form
associations of galaxies in rare overdense regions and the realm of the
galactic world is stretched into relatively lower-density regions along
evolving filaments. The cosmic web of galaxies forms at lower redshifts when
most rhizomes globally percolate. The primordial angular momentum produced by
the induced tidal torques on protogalactic regions is correlated with the
internal kinematics of galaxies and tightly aligned with the angular momentum
of the total galaxy mass. The large-scale tidal field imprinted in the initial
conditions seems responsible for the dominance of disk morphology, and for the
tendency of galaxies to re-acquire a disk post-distortion.
