Regna firmat pietas

Regna firmat pietas (Danish: Fromhed styrker rigerne, Low German: Die Gotts Fruchtigkeit machet veste Reiche, abbreviated to R.F.P.) is a Latin phrase translated in English as "Piety strengthens the realms".^[1] The phrase was used as the royal motto for Denmark–Norway during the reign of Christian IV and sought to promote Lutheranism as a strength for the nation.^[1]

King Christian used the phrase for the first time in 1584 when he was seven, and likely adopted it from his teacher, Hans Mikkelsen.^[2] The motto can be found in buildings and churches erected by King Christian in Denmark, Norway and Schleswig-Holstein.^[2] In Holmen Church, Copenhagen, where many Danish national heroes are buried, the motto stands visibly over the chapel's entrance,^[3] and it is also showcased with its initials R.F.P. on the Rundetaarn.^[4]

The motto was also showcased on coins during Christian IV's reign.^[5]