Annals I.17

At last, when there were others ready to be abettors of a mutiny, he asked, in the tone of a demagogue, why, like slaves, they submitted to a few centurions and still fewer tribunes. "When," he said, "will you dare to demand relief, if you do not go with your prayers or arms to a new and yet tottering throne? We have blundered enough by our tameness for so many years, in having to endure thirty or forty campaigns till we grow old, most of us with bodies maimed by wounds. Even dismissal is not the end of our service, but, quartered under a legion's standard we toil through the same hardships under another title. If a soldier survives so many risks, he is still dragged into remote regions where, under the name of lands, he receives soaking swamps or mountainous wastes. Assuredly, military service itself is burdensome and unprofitable; ten ases a day is the value set on life and limb; out of this, clothing, arms, tents, as well as the mercy of centurions and exemptions from duty have to be purchased. But indeed of floggings and wounds, of hard winters, wearisome summers, of terrible war, or barren peace, there is no end. Our only relief can come from military life being entered on under fixed conditions, from receiving each the pay of a denarius, and from the sixteenth year terminating our service. We must be retained no longer under a standard, but in the same camp a compensation in money must be paid us. Do the praetorian cohorts, which have just got their two denarii per man, and which after sixteen years are restored to their homes, encounter more perils? We do not disparage the guards of the capital; still, here amid barbarous tribes we have to face the enemy from our tents."

Here Percennius, the leaders of the mutany, presents the soldiers' complaints. They want more pay. But what exactly happened?

Let's go back it time a little. The year is now AD 14. Augustus just died and Tiberius just became emperor. We don't know when exactly the mutany takes place. As we just read, Tiberius was taking time claiming the full powers of emperor, for whatever reasons, fake or real. The event could have easily hastened Tiberius' decission to ascend.

But if we go back in time a little to AD 6-9, we find there was a rebellion in Illyricum. In fact, some call it the Great Illyrian Revolt. These soldiers saw hard action. Additionally, Tiberius and Germanicus both fought there as well, so they know the land, the war and the soldiers.

The most important line in the passage is "under the name of lands, he receives soaking swamps and mountainous wastes." Under Augustus, veterans were receiving nice Italian lands. Apparently, Augustus ran out of good land and started assigning provincial land in Illyricum. The policy was likely Augustus' and now the soldiers are appealing to Tiberius.

It's important to note that the soldiers are not looking to overthrow Tiberius. In fact, since Tiberius fought with them, they may be loyal to him. They just want higher pay and better lands.