Christopher Cooper stole items including crucifixes, bibles and a stone coffin over a three-year period.
He targeted churches in Warwickshire and is thought to have made around £150,000 by selling the goods to collectors.
Cooper, 48, would pretend to be a visitor before leaving and returning later in the day.
He stole more than 30 stone, glass, and wooden relics dating from as far back as the 9th Century.
Many of the churches he stole from were not aware that items had gone missing until police recovered them during a country-wide investigation, called Operation Icarus.
He was jailed at Hereford Crown Court after previously admitting fraud, theft, and dealing in tainted cultural objects.
Property stolen included historical artefacts from early medieval and Saxon times and Tudor periods including a medieval stained glass wooden frame and an ancient crucifix as well as a brass knight and coat of arms.
Stephen Davies, West Midlands district crown prosecutor said: "Some of the churches did not notice (the thefts) and this is why there has been an extensive attempt by police to highlight these items."
While many of the churches have had their items returned, many collectors have lost their money.