Hippolytus of Rome (170 - 235 AD) was one of the most important 3rd-century theologians in the Christian Church in Rome, where he was probably born. Photios I of Constantinople describes him in his Bibliotheca (cod. 121) as a disciple of Irenaeus, who was said to be a disciple of Polycarp, and from the context of this passage it is supposed that he suggested that Hippolytus so styled himself. However, this assertion is doubtful.

As a presbyter of the church at Rome under Pope Zephyrinus (199 - 217 AD), Hippolytus was distinguished for his learning and eloquence. It was at this time that Origen of Alexandria, then a young man, heard him preach.  He accused Pope Zephyrinus of modalism, the heresy which held that the names Father and Son are simply different names for the same subject. Hippolytus championed the Logos doctrine of the Greek apologists, most notably Justin Martyr, which distinguished the Father from the Logos ("Word"). An ethical conservative, he was scandalized when Pope Callixtus I (217 - 222 AD) extended absolution to Christians who had committed grave sins, such as adultery.  Hippolytus himself advocated an excessive rigorism. At this time, he seems to have allowed himself to be elected as a rival Bishop of Rome, and continued to attack Pope Urban I (222 - 230 AD) and Pope Pontian ( 230 - 235 AD). G. Salmon suggests that Hippolytus was the leader of the Greek-speaking Christians of Rome. Allen Brent sees the development of Roman house-churches into something akin to Greek philosophical schools gathered around a compelling teacher.  Under the persecution at the time of Emperor Maximinus Thrax, Hippolytus and Pontian were exiled together in 235 AD to Sardinia, likely dying in the mines. It is quite probable that, before his death there, he was reconciled to the other party at Rome, for, under Pope Fabian (236-250), his body and that of Pontian were brought to Rome. The so-called chronography of the year 354 (more precisely, the Catalogus Liberianus, or Liberian Catalogue) reports that on August 13, probably in 236 AD, the two bodies were interred in Rome, that of Hippolytus in a cemetery on the Via Tiburtina, his funeral being conducted by Justin the Confessor. This document indicates that, by about 255 AD, Hippolytus was considered a martyr and gives him the rank of a priest, not of a bishop, an indication that before his death the schismatic was received again into the Church.

Answer the following question by taking a quote from the article: who did he die with?
Pontian