Henry II the Rich (c. 1190–1251; German: Heinrich II. der Reiche, Dutch: Hendrik II de Rijke) was Count of Nassau between 1198 and 1249.
Henry II was the eldest son of Count Walram I of Nassau. He was born around 1190, according to most sources (A.W.E. Dek gives his birth date as ca. 1180, which is plausible since his father was away at the Third Crusade in 1189-1190). His mother was Kunigunde of Ziegenhain (a town now part of Schwalmstadt, Hesse), daughter of Count Poppo II of Nidda. Upon his father’s death in 1198, Henry succeeded him at the age of eighteen as Count (German: Graf) of Nassau. He shared the reign with his younger brother, Robert IV, until 1239.
In the politics of the Holy Roman Empire, Henry was generally a loyal supporter of the Hohenstaufen emperors. However, between 1209 and 1211, he backed the rival Otto IV of Brunswick as emperor, before reverting sides to support Frederick II. Between 1212 and 1214, he held prisoner Frederick's (and his own) opponent, the Archbishop of Trier Theodoric II (also known as Dietrich of Wied).
Towards the end of the 12th century, Walram I had been able to strengthen his power on the lower Lahn. As part of the inheritance of the Counts of Arnstein, he succeeded them as the Archbishopric of Trier's Vogt in Koblenz, Pfaffendorf (now a borough of Koblenz), Niederlahnstein, and Humbach (Montabaur). However, by the 1230s, Trier's influence near the Rhine and Lahn had strengthened enough to oust Nassau from the majority of the Archbishopric's vogtships. The Archbishop had reinforced Montabaur around 1217 in order to protect his possessions on the right bank of the Rhine from Nassau.