William IV had a successor in the United Kingdom and in Hanover.
As king, William used the royal coat of arms of the United Kingdom undifferenced: Quarterly, I and IV Gules three lions passant guardant in pale Or (for England); II Or a lion rampant within a tressure flory-counter-flory Gules (for Scotland); III Azure a harp Or stringed Argent (for Ireland); overall an escutcheon tierced per pale and per chevron (for Hanover), I Gules two lions passant guardant Or (for Brunswick), II Or a semy of hearts Gules a lion rampant Azure (for Lneburg), III Gules a horse courant Argent (for Westphalia), overall an inescutcheon Gules charged with the crown of Charlemagne Or, the whole escutcheon surmounted by a crown
 When Frederick died in 1827, William, then more than 60 years old, became heir presumptive

