There are few answers to your question in the Bible, but I will give you the ones I know.
First of all in:
Revelation 1:1 KJV
The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants
things which must shortly come to pass; and he sent and signified it by his angel unto his
We are told that things were to happen soon, but we do not have any definition of what is meant by soon. and we are told in:
Revelation 1:19 KJV
Write the things which thou hast seen, and the things which are, and the things which shall be hereafter;
that some of those things were happening now, which may refer to the Church age which we are in now, and some of them will happen later, which I take to be a future age such as the period of the tribulation.
The Revelation breaks down into three parts things that are, things that were, and things which will be.
The millennium to which you refer comes in the things which will be category.
Most Protestants with whom I have talked believe in pre millennialism, based on the following Scriptures, but I do not know about Catholics.
Job 14:12 KJV
So man lieth down, and riseth not: till the heavens be no more, they shall not awake, nor be
raised out of their sleep.
Mat 24:21 & 22 KJV
21 For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.
22 And except those days should be shortened, there should no flesh be saved: but for the elect's sake those days shall be shortened.
Mat 24:29 through 31 KJV
29 Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken:
30 And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.
31 And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.
Mat 25:31 KJV
When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory:
This is the beginning of both the Bema judgment and on into the Great white throne judgment.
Most Protestants that I have talked to feel that Matthew 24:22 indicates that God will take his people from the Earth prior to the Great Tribulation, they believe that a loving God would not have his believers go through that, and I am inclined to agree with that assumption.
There is no clear answer to exactly when this will happen, but since Jesus said:
Mat 24:36 KJV
But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.
I hope this is a satisfactory answer, since there is no Biblical answer of which I know.