Please answer a question about the following article about Frederic Chopin:

At the funeral of the tenor Adolphe Nourrit in Paris in 1839, Chopin made a rare appearance at the organ, playing a transcription of Franz Schubert's lied Die Gestirne. On 26 July 1840 Chopin and Sand were present at the dress rehearsal of Berlioz's Grande symphonie funebre et triomphale, composed to commemorate the tenth anniversary of the July Revolution. Chopin was reportedly unimpressed with the composition.

What anniversary was the July Revolution that Sand and Chopin were present at a dress rehearsal for?
tenth