ten Kings of Persia; Cyrus, Cambyses, &c.  Reigned 208 years, which is almost 21 years a piece.  The sixteen Successors of Alexander the great, and of his brother and son in Syria; Seleucus, Antiochus Soter, &c.  Reigned 244 years, after the breaking of that Monarchy into various Kingdoms, which is 151/4 years a-piece.  The eleven Kings of Egypt; Ptolomaeus Lagi, &c.  Reigned 277 years, counted from the same Period, which is 25 years a-piece.  The eight in Macedonia; Cassander, &c.  Reigned 138 years, which is 171/4 years a-piece.  The thirty Kings of England; William the Conqueror, William Rufus, &c.  Reigned 648 years, which is 211/2 years a-piece.  The first twenty four Kings of France; Pharamundus, &c.  Reigned 458 years, which is 19 years a-piece:  the next twenty four Kings of France; Ludovicus Balbus, &c. 451 years, which is 183/4 years a-piece:  the next fifteen, Philip Valesius, &c. 315 years, which is 21 years a-piece:  and all the sixty three Kings of France, 1224 years, which is 191/2 years a-piece.  Generations from father to son, may be reckoned one with another at about 33 or 34 years a-piece, or about three Generations to an hundred years:  but if the reckoning proceed by the eldest sons, they are shorter, so that three of them may be reckoned at about 75 or 80 years:  and the Reigns of Kings are still shorter, because Kings are succeeded not only by their eldest sons, but sometimes by their brothers, and sometimes they are slain or deposed; and succeeded by others of an equal or greater age, especially in elective or turbulent Kingdoms.  In the later Ages, since Chronology hath been exact, there is scarce an instance to be found of ten Kings Reigning any where in continual Succession above 260 years:  but Timaeus and his followers, and I think also some of his Predecessors, after the example of the Egyptians, have taken the Reigns of Kings for Generations, and reckoned three Generations to an hundred, and sometimes to an hundred and twenty years; and founded the Technical Chronology of the Greeks upon this way of reckoning.  Let the reckoning be reduced to the course of nature, by putting the Reigns of Kings one with another, at about eighteen or twenty years a-piece:  and the ten Kings of Sparta by one Race, the nine by another Race, the ten Kings of Messene, and the nine of Arcadia, above mentioned, between the Return of the Heraclides into Peloponnesus, and the end of the first Messenian war, will scarce take up above 180 or 190 years:  whereas according to Chronologers they took up 379 years.