Jesus said, "Ye shall have tribulation ten
days". It could mean that the Early Church
had suffered ten major persecutions under
ten different rulers.

Or it could mean that the Church experienced
severe persecution from 303-313 A.D. (A day
is sometimes considered a year in prophecy.)
Numbers 14:33-34 In 303 the emperor issued
destruction of the churches, burning the the
scriptures and death to the Christians. It ended
when Constantine came to rule. He accepted
Christianity in the year 312 A.D. and became
emperor the next year.