Isaac Troki composed, in 1593, a work entitled "The Strengthening of Faith" (_Chizzuk Emunah_), in which the author defended Judaism and attacked Christianity.

It was a lucid book, and as its arguments were popularly arranged, it was very much read and used.

With this exception, Karaism produced no important work after the twelfth century.
On the intellectual side, therefore, Karaism was a powerful though ephemeral movement.

In several branches of science and philology the Karaites made real additions to contemporary knowledge.

But the main service of Karaism was indirect.