How many times was Paul the apostle imprisoned in Rome?

During Paul's second missionary journey (late 49 A.D.) he sepnt an unspecified time in a Philippians jail cell with fellow evangelist Silas

Paul is arrested in 58 A.D. by Roman troops who save him from being killed in a temple riot. He is taken to Caesarea where he spends a little more than two years in prison

In 60 or 61 A.D. Paul is taken as prisoner to Rome. When his case is heard he is acquitted in the Spring of 63. A.D. ( He was under house arrest)

In 66 or 67 A.D. Paul is again a Roman prisoner in the city of Rome. Paul stays in jail until he is put to death under Nero by the Romans around 68 A.D.

During his ministry the Apostle Paul spent roughly 5 1/2 to 6 years as a prisoner or in prison.