It was useless to look for help or justice in England, and that very night Thomas left England for Flanders to appeal to Rome.
But Pope Alexander could do no more for Thomas than his predecessor had done for Anselm; only he would not allow any resignation from Canterbury.
Henry himself appealed to the Pope in 1166, fearing excommunication by the Archbishop; "thus by a strange fate it happened that the King, while striving for those 'ancient customs' by which he endeavoured to prevent any right of appeal (to the Pope), was doomed to confirm the right of appeal for his own safety." The Pope did what he could to arrange a reconciliation, but it was not till 1170 that the King, seriously alarmed that Thomas would place England under an interdict, agreed to a reconciliation.
On December 1st the exile was over, and Thomas landed at Sandwich, and went at once to Canterbury.

There were many who doubted whether there could be lasting peace between the King and the Archbishop, and while the bishops generally hated the Primate's return, the nobles spoke openly of him as a traitor to the King.
The end was near.

Thomas, asked to withdraw the sentence of excommunication he had passed against the Archbishop of York and the Bishop of London and Salisbury for violating the privileges of Canterbury, answered that the matter must go before the Pope.

The bishops, instead of going to Rome, hastened to Henry, who was keeping his Court at Bur, in France.
Henry, at the complaint of the bishops, broke out into one of those terrible fits of anger which overcame him from time to time, and four knights left the Court saying, "All this trouble will be at an end when Thomas is dead, and not before." On December 29th these knights were at Canterbury, and at nightfall, just when vespers had begun, they slew Archbishop Thomas by the great pillar in the Cathedral.

So died this great Archbishop for the liberties of the Church, and, as it seemed to him, for the welfare of the people.
Henry was horrified at the news of the Archbishop's death, and hastened to beg absolution from Rome for the rash words that had provoked the murder.
In the presence of the Papal legate he promised to give up the Constitutions of Clarendon, nor in the remaining eighteen years of his reign did Henry make any fresh attempt to bring the Church under the subjection of the Crown.
To the great bulk of English people Thomas was a saint and martyr, and numerous churches were dedicated in his name.