Quaerite Regnum Dei, Latin for «Seek ye the Kingdom of God», is the calligaphic style font based on a beautiful medieval Spanish rotunda (16th century) hand found in the Misal rico de Cisneros. In the early 16th century, Francisco Jiménez de Cisneros, who was a cardinal in Spain, commissioned local monks/scribes to create a missal to be used in his Toledo cathedral.
The result is held by the Spanish National Library, who graciously created high resolution scans of it available to the whole world.
As this font is meant to look like handwriting, Quaerite Regnum Dei includes multiple versions of each letter and also includes OpenType features which make it so that when two letters appear together, such as "aa", the second "a" will look different than the first "a". So, the font contains two of each lowercase letter; some, such as ‹s›, have 5 alternates.