Apparently, she wrote about memory in relation to action, history and the Greeks in The Human Condition. I haven't read it, but here is a quote from the Stanford Encyclopedia of Philosophy: "One of the principal drawbacks of action, Arendt maintains, is to be extremely fragile, to be subject to the erosion of time and to forgetfulness; unlike the products of the activity of work, which acquire a measure of permanence by virtue of their sheer facticity, deeds and words do not survive their enactment unless they are remembered. Remembrance alone, the retelling of deeds as stories, can save the lives and deeds of actors from oblivion and futility. And it is precisely for this reason, Arendt points out, that the Greeks valued poetry and history so highly, because they rescued the glorious (as well as the less glorious) deeds of the past for the benefit of future generations (HC, 192 ff; BPF, 63–75). "