1) "And I stood on the sand of the sea, and saw a beast (kingdom) rise up out of the sea, having seven heads and ten horns, and upon his horns ten crowns, and upon his heads the name of blasphemy. 2) And the beast that I saw was like unto a leopard, and his feet were as the feet of a bear, and his mouth as the mouth of a lion; and the dragon gave him his power, and his seat (throne) and great authority. 3) And I saw one of his heads as it were (slain) wounded to death,(εσφαγμενην), and his deadly wound was healed: and all the world wondered after the beast."
John is instructed to document and record a series of events: the things which he had seen, the things that are, and the things which shall be hereafter. (Revelation 1:19). After the seven letters to the seven churches, John is shown a door in heaven and is taken in the spirit. The large majority of the things recorded in Revelation consists of futuristic events, that extended far beyond John's world, to the end of the age. These events transpire during the appointed time of tribulation and move the reader forward, into the Great tribulation.
I think most people are shocked when they discover the reveal contained in Revelation is more literal than it's given credit for. The use of symbology is a viewing of 'things which shall be hereafter,' witnessed and recorded by John while he is in the spirit on the Lords day.
And the dragon was wroth with the woman (Israel) and went to make war with the remnant of her seed, which keep the commandments of God, and have the testimony of Jesus Christ. Rev 12:17 (See also Genesis 3:15)
As Satan's war on the Christians and the Jews escalates, John is shown the rise of a beast kingdom. John stands on the sands of the sea 13:1, as he witnesses the rise of a great beast with seven heads and ten horns in the end of days. Several translations such as Darby document the dragon aka: Satan standing on the sands of the sea orchestrating the rise of his beast kingdom as John bears witness.
And I (John) stood upon the sand of the sea and saw a beast (kingdom) rise up out of the sea, having seven heads (four beast kingdoms and three non-beast kingdoms) and ten horns (ten kings), and upon his horns ten crowns (authority, power), and upon his heads the name of blasphemy.