What made Saint Cecilia become a saint?

Cecilia was not canonized. She was proclaimed a saint by early Christians because of her martyrdom. At first, the Roman authorities tried to kill her by suffocation but after 3 days in a hot, steamy sauna she was still alive. Next they tried to behead her but, after three tries, she was mortally wounded but still alive. During the next three days, while she lay dying, she arranged to have all her wealth distributed to the poor.

The canonization process did not come into existence until the 12th century. In the primitive Church, martyrs were immediately recognized as witnessing to the perfection of Christian life on earth, having shown the ultimate proof of their love for Christ by the offering of their lives. By the sacrifice of their lives

for Christ, they attained Heaven in eternal glory and were indissolubly

united to the Lord, the Head of the Mystical Body.
Cecilia had been condemned to die because she was a Christian. First they tried to suffocate her by leaving her in a sauna. That did not work so a soldier tried to cut off her head three times - the maximum allowed by Roman law. Although seriously wounded, she lay three days before she died. During this time she made arrangements for her wealth to go to the Church to help the poor.

Cecilia earned her sainthood by dying for her faith.

Additional Information:

Saint Cecilia was an early Chrisitan who died for her faith as a martyr. She would have been declared a saint by popular acclamation. Martyrs were always considered automatic saints. There was no offical canonization process in place at the time.

In the primitive Church, martyrs were immediately recognized as witnessing to the perfection of Christian life on earth, having shown the ultimate proof of their love for Christ by the offering of their lives. By the sacrifice of their lives for Christ, they attained Heaven in eternal glory and were indissolubly united to the Lord, the Head of the Mystical Body.
Saint Cecilia was an early Chrisitan who died for her faith as a martyr. She would have been declared a saint by popular acclamation. Martyrs were always considered automatic saints. There was no offical canonization process in place at the time.

In the primitive Church, martyrs were immediately recognized as witnessing to the perfection of Christian life on earth, having shown the ultimate proof of their love for Christ by the offering of their lives. By the sacrifice of their lives for Christ, they attained Heaven in eternal glory and were indissolubly united to the Lord, the Head of the Mystical Body.
St. Cecilia refused to deny her Catholic faith and was condemned to die. She was a martyr for her faith and that is nearly an automatic way to obtain sainthood. There was no formal process for canonization when she was killed so would have been declared a saint by popular acclamation soon after she died.

Additional Information:

Saint Cecilia was an early Chrisitan who died for her faith as a martyr. She would have been declared a saint by popular acclamation. Martyrs were always considered automatic saints. There was no offical canonization process in place at the time.

In the primitive Church, martyrs were immediately recognized as witnessing to the perfection of Christian life on earth, having shown the ultimate proof of their love for Christ by the offering of their lives. By the sacrifice of their lives for Christ, they attained Heaven in eternal glory and were indissolubly united to the Lord, the Head of the Mystical Body.