The tradition of setting up the royal arms in church goes back to the Reformation when Protestant iconoclasts swept away everything they regarded as idolatrous, including the rood or crucifix set up on the rood screen that separated the nave from the chancel.
When Henry VIII finally broke with Rome, someone had the brilliant idea of replacing the rood with the royal arms, which are both decorative and a very public statement of loyalty to the new Head of the Church of England.
As time went on, rood screens themselves fell out of favour and were mostly removed, the royal arms being moved to less prominent places in the nave.
At Racton church, however, the royal arms remain in their original position over the roof beam that is the only division between nave and chancel, although the current arms are those of George II and date from the mid-18th century, as does the lovely lacy tracery on either side.
The royal arms could be very provocative in the centuries following the Reformation. At Burton church, the arms of Charles I are painted in the plaster with the admonition “Obey them that have the Rule over you, Heb, 13, 17” inscribed above. It was lucky the church was hidden within the park of the great house of the Royalist Goring family, or it would almost certainly have been erased in the Commonwealth years.
The arms of most monarchs since then are represented in local churches.
William III is in Aldingbourne, which also has the arms of George III. Both have been recently restored.
Queen Anne’s arms are at Midhurst.
The arms of George III with particularly lively lion and unicorn, are at Slindon.
Coats of arms were usually painted by itinerant sign painters whose main line of business was inn signs. Exposed to the weather, few inn signs survive so the royal arms in churches are often all we have of the work of these craftsmen.
According to Norman Pound’s History of the English Parish, it was never compulsory in law to put up the royal arms in churches, but curiously a big court case erupted over plans by many churches to put up the arms of Elizabeth II to celebrate the coronation in 1953.
West Tarring church in Worthing applied to the diocese for a faculty to erect the royal arms, which was granted, but the government then intervened saying the Queen’s permission was also needed. The Queen evidently approved, because her arms adorn the nave to this day.