Athenian hoplites' widows

My sister told me that she had read that the widows of Athenian hoplites
who had died in battle were excused paying civic taxes for the rest of
their lives. Attempts to verify this with a web search failed between the
Scylla of complaints about modern Greek taxation and the Charybdis of
myriad papers on gender studies. Does anyone know whether it's true? Thanks
in advance.

RH