People worshiped the dragon because he had given authority to the beast, and they also worshiped the beast and asked, “Who is like the beast? Who can wage war against it?”
Revelation 13:4
The beast of Revelation is one of frequent controversy, yet it should be interpreted in the context of the book. In the context of what we are looking at, we are looking at the destruction of Jerusalem in 70AD, and the winepress of God’s wrath at the end of Revelation 14 as Betar in 135AD (see here for discussion).
This leaves a window of approximately 60 years, after the fall of Jerusalem.
As it happens, Nero was killed by a fatal head wound, after stabbing himself in the neck with his own sword. He was a monster. When Domitian came along later in the 90s, he was looked at as Nero back from the dead. Both were considered insane, and both fiercely persecuted Christians.
Further, Domitian required that everyone burn a pinch of incense and declare “Caesar is Lord”, and they would receive a certificate (called the “mark of the emperor”) so that they could buy or sell.
Further, the cult of the emperor enforced emperor worship. Temples existed for the worship of the emperor, and a statue was set up.
It seems fairly clear, in the study of history, if one accepts an early date for the writing of the book of Revelation, that the person that the populace then referred to as a “beast” (Domitian) would be the beast back from the pit (Nero raised from the dead), that required a mark for the buying and selling, to whom the dragon had given his authority.
The beast of Revelation 13 was Domitian, in some how, Nero back from the pit, and his mark is a point of history.