The Gemara (Berachos 31a) learns from a verse that Daniel that prayed three times a day. From then on (i.e. throughout the entire times of the second Mikdash), it appears that everyone Davened three times a day. Even before that, during the times of the First Mikdash, the people certainly Davened regularly - at least according to those who maintain that it is a Mitzvah d'Oraisa to Daven every day (see Rambam, beginning of Hilchos Tefilah).

The Rambam (Hilchos Tefilah 1:4) writes that the Anshei Keneses ha'Gedolah instituted the exact text for the daily Tefilah after the destruction of the first Mikdash since Jews became less familiar with Lashon ha'Kodesh, and were not able to pray with clarity in Hebrew on their own.

Attached is an answer that the Kollel prepared in the past which contains a number of points that relate to your question. It can be found online at http://www.dafyomi.co.il/berachos/discuss/bera-058.qa5.pdf .

Best wishes,

M. Kornfeld

Kollel Iyun Hadaf