Rashi: These are the Bavliyim, who gored Yehudah and with their horns, until Zirum (they strewed them).

Radak: They gored it until they strewed them here and there. Each of the horns [kingdoms] did evil to them in its time. Even though Malchus Paras raised Yisrael from Galus at the start of their kingdom, afterwards they did evil to them in the days of the first Artachshasta and in the days of Achashverosh, until Daryavesh's second year.

Malbim: It uses the image of horns, because they gored the scattered Seh 9sheep or goat] Yisrael with their horns, like it says "v'Karnei Re'em Karnav Bahem Amim Yenagach" (Devarim 33:17). Also, in every Keren (corner) of the world, there is a horn to gore Yisrael and scatter them. Nevi'im discussed four kingdoms, corresponding to the directions, as if one kingdom rules over each direction. Even though usually, one kingdom overpowers and rules over the entire world, we find that each is associated with one of the directions. Nevi'im depicted that the upper Sarim that influence on the kingdom stand in four levels, and they are arranged in the supreme Merkavah of the four directions. Each faces a special direction. He was shown that during the entire duration of the Galus will be found four Keranos that gore Yisrael in the four directions.