• Born: Between 1010 and 1021, Vlaardingen, Zuid Holland, Netherlands
• Married: Abt 1050
• Died: 28 Jun 1061, Hamerth (i.e. Nederhemert), Gelderland, Netherlands

  Research Notes:

The Annales Egmundani names "Florentius I" as brother of "Theodericus IIII comes filius Theoderici et Othelhildis" when recording that he succeeded his brother. No source has been identified which indicates Floris’s birth date. However, recent examination of his skeleton has revealed that he was aged between 40 and 50 years old when he died, which would place his birth in [1010/21]. His estimated marriage date suggests his birth in the later part of this estimated birth date range. The Chronologia Johannes de Beke names "Theodricum succedentem Hollandia principum et Florencium Orientalis Frisie comitem" as children of Count Dirk III & his wife. "Heinricus…rex" confirmed a treaty between Wilhelm Bishop of Utrecht and Reginbert Abbot of Echternach under which they recognised each other's rights in "Flardinge, Kiericwerve, Velsereburc, Heligelo, Pethem" by charter dated 28 Dec 1063 which names "Theoderico comite ac filio eius Theoderico fratreque eius Florencio".

He succeeded his brother in 1049 as FLORIS I Count of Holland.

The Annales Egmundani record that "Florentius comes Hollandensis" was killed in 1061 at "Hamerthe". The Chronologia Johannes de Beke records the death "1061…in Hamerth…XIV Kal Iun" of Count Floris and his burial at Egmond. Beke's Egmondsch Necrologium records that "Florentius primus Hollandie comes" was killed in battle "1061 IV Kal Iul". ¹