The 3.5 year time of peace comes 1/2 way thru a 7 year peace treaty with Israel . The treaty is broken 3.5 years in and then all hell breaks lose.
So, should we hear about a 7 year treaty with Israel, stay aware.
Daniel's 25 And he will [aa]speak against the Most High and wear down the [ab]saints of the Highest One, and he will intend to make alterations in times and in law; and [ac]they will be handed over to him for a [ad]time, [ae]times, and half a [af]time.
3.5 years - the Jewish-Roman war started in February 67 AD and ended in August 70 AD - 3.5 years
The half-way through doesn't corroborate with the text in Daniel 9: 27 And he will confirm a covenant with the many for one week, but in the middle of the week he will put a stop to sacrifice and grain offering; and on the wing of [af]abominations will come the one who [ag]makes desolate, until a complete destruction, one that is [ah]decreed, gushes forth on the one who [ai]makes desolate.”Note that there is no gap between the 69th and the 70th weeks -- Luke testifies that the prophecy of Daniel was accomplished at th teim when Jerusalem was overthrown -- Daniel is talking of the fall of Jerusalem in 70 AD and before that - 35 odd years earlier, of the death of the Messiah and His resurrection as the mountain that covers the world