Thessalonica (СОЛУНЬ in Russian), developed by Alexej Kryukov, is a set of keyboard input methods and converters which enable writing, among others, polytonic (classical) Greek, Arabic, and Hebrew. The most advanced version is a module for the office suite OpenOffice.org (similar and compatible to MS Office). It is distributed under the conditions of the GNU General Public License.
The combination of OpenOffice.org and Thessalonica can be used on several platforms, including Windows and Linux.
The most recent version of Thessalonica for OpenOffice.org is 2.9/3.0 beta (2008/11/18), requiring at least OpenOffice.org 2.1 with Java JRE 1.5 or higher. The distribution includes converter description files for WinGreek and WinLanguage Polytonic Greek encodings; other special conversions are programmable.
There is an independently developed and freely downloadable Syriac Input Method which uses Thessalonica under OpenOffice to allow users to type Syriac characters, points and marks directly into their documents alongside text in other languages and orthographies.
See also: Thessalonica website