A martyr is one who is killed for believing in their religion
No. St. Anthony of Padua was not a martyr. He died of natural causes.
He was a martyr for his cause, and died believing in it.
Weston Martyr died in 1966.
Romulus - martyr - died in 112.
Harold - martyr - died in 1168.
Charbel - martyr - died in 107.
Sophia the Martyr died in 137.
Sarah the Martyr died in 303.
Orentius - martyr - died in 304.
Zosimus - martyr - died in 110.
Stephen could be considered the first Christian martyr. His story is told in Acts 6-7