Unusually, the kings are poised to pay homage rather than doing so, and Joseph - or it may be Saint John the Baptist - prominently points to Christ.
The peaks at the extreme right were originally intended as towers. In front a tiny angel appears on a cloud, presumably to announce the Nativity to the shepherds.
A grid and diagonals converging on the vanishing point are incised. Bramantino worked in Milan and this painting probably dates from the 1490s.