Short answers, pulled from the story.
August Mau developed the four-style classification system for Pompeian wall paintings in the late 19th century. He was a German archaeologist born in 1840 and died in 1909 who studied the massive collection of surviving Roman frescoes at the site.
The First Style began around 200 BC with stucco molding that rose from plaster surfaces to create the illusion of expensive marble veneering on ordinary stone. Painters used vivid colors like yellow, purple, and pink to mimic different types of cut stone while wealthy homeowners could afford suspended alabaster discs or white pillars painted onto their walls.
Painters in the first century BC applied trompe-l'œil techniques to flat plaster surfaces to make viewers feel as though they were looking out of a window at a real scene. Columns painted in Ionic styles divided the wall space into distinct zones where false architectural elements opened up wide expanses for artistic compositions.
A delicate linear fantasy replaced the three-dimensional worlds of the previous period around 20 BC by leaving vast areas of the wall plainly colored with no design whatsoever. Symmetry dictated every element through strict rules dividing walls into horizontal and vertical zones where slender columns of foliage hung around candelabra or fluted appendages decorated the spaces.
The House of the Vettii displayed an Ixion Room painted between 60 AD and 79 AD which represents the final phase that revived large-scale narrative painting while integrating architectural details from earlier eras. The eruption of Mount Vesuvius in 79 AD covered Pompeii in ash before development could continue elsewhere.