Map of the Roman Empire in 125 during the reign of emperor Hadrian.
Projection
Lambert azimuthal-equal area. Central latitude: 45° N, central longitude: 20° E. X, Y origin offset - 0
Datum: ETRS89
Sources
The physical map was made using the following public domain sources:

Topography: NASA Shuttle Radar Topography Mission (SRTM30) data 
Shoreline, lakes and rivers: derived from Natural Earth dataAdditional references for the map content:

Tacitus, Germania (ca. 100)
Ptolemy, Geographia (ca. 140)
Atlante storico DeAgostini, Instituto Geografico DeAgostini, 1998. pg. 35-41.
Historischer Weltatlas, Dr. Walter Leisering, Marix Verlag, 2011. pg. 26-27
Történelmi világatlasz, Cartographia Kiadó, 2005. pg. 20-21.
The Penguin Historical Atlas of Ancient Rome by Christopher Scarre, Penguin Historical Atlases, 1995. pg. 81.Software used
GIS:

Open JUMP GIS (open source): http://www.openjump.org/
GRASS GIS (open source): http://grass.osgeo.org/Graphics editors:

Inkscape (open source): http://inkscape.org/
GIMP (open source): http://www.gimp.org/
Own work
User:Andrein, with the assistance of EraNavigator