We use photometric and spectroscopic observations of the eclipsing binaries V65 , V66 and V69 in the field of the globular cluster M4 to derive masses , radii , and luminosities of their components .
The orbital periods of these systems are 2.29 , 8.11 and 48.19 d , respectively .
The measured masses of the primary and secondary components ( M _ { p } and M _ { s } ) are 0.8035 \pm 0.0086 and 0.6050 \pm 0.0044 M _ { \odot } for V65 , 0.7842 \pm 0.0045 and 0.7443 \pm 0.0042 M _ { \odot } for V66 , and 0.7665 \pm 0.0053 and 0.7278 \pm 0/0048 M _ { \odot } for V69 .
The measured radii ( R _ { p } and R _ { s } ) are 1.147 \pm 0.010 and 0.6110 \pm 0.0092 R _ { \odot } for V66 , 0.9347 \pm 0.0048 and 0.8298 \pm 0.0053 R _ { \odot } for V66 , and 0.8655 \pm 0.0097 and 0.8074 \pm 0.0080 R _ { \odot } for V69 .
The orbits of V65 and V66 are circular , whereas that of V69 has an eccentricity of 0.38 .
Based on systemic velocities and relative proper motions , we show that all the three systems are members of the cluster .
We find that the distance to M4 is 1.82 \pm 0.04 kpc - in good agreement with recent estimates based on entirely different methods .
We compare the absolute parameters of V66 and V69 with two sets of theoretical isochrones in mass-radius and mass-luminosity diagrams , and for an assumed [ Fe/H ] = -1.20 , [ \alpha /Fe ] = 0.4 , and Y = 0.25 we find the most probable age of M4 to be between 11.2 and 11.3 Gyr .
CMD-fitting with the same parameters yields an age close to , or slightly in excess of , 12 Gyr .
However , considering the sources of uncertainty involved in CMD fitting , these two methods of age determination are not discrepant .
Age and distance determinations can be further improved when infrared eclipse photometry is obtained .

Key words : binaries : close – binaries : spectroscopic – globular clusters : individual ( M4 ) – stars : individual ( V65-M4 , V66-M4 , V69-M4 )