How many are familiar with him?
Yes.
I would argue that this has been the greatest influence on all that is good in both Christianity and Islam, and thus provides a great foundation for mutual dialog...
I'd rather suggest the contemplation of Christ has been the greatest and most profound mystical influence, as has the repetition of the Divine Name, and prayer ... The Liturgy ...
In terms of theology, probably 1 Corinthians 13:13 – Faith, Hope and Love – the discussion of the lexical technicalities of 'agape', like those concerning 'Logos' are of profound interest, especially to the 'Christian Platonist' – but quite rightly Clement of Alexandria said 'philosophy is the handmaid of theology'.
In terms of mystical contemplation – 1 Corinthians 13:12, and undoubtedly 1 John 3:2.
Philosophy, notably Platonism in all its forms, contributed a lexicon that assisted apologists in defending and explaining the Deposit of Faith as both reasonable and rationable, if essentially and ontologically mysterious – but that is after the fact, as it were – Platonic models are useful analogies to help explain the Trinity, but the vast majority of Christendom are not interested in such complexities, and rightly so.
The Church could arguably do without philosophy, not a strong argument in my book, but then I'm pro-philosophy – I rather see it as providential – but it cannot do without the Eucharist.
And much as I delight in discussions of implications for the Trinity found in the Enneads (I've written reams that I've never bother to post here as being too long and too technical)' of monad and henad, I rather think it is, and always has been too niche to be considered 'the greatest influence' ... but I'd delight to see that validated.
Historically, philosophy has been a mixed blessing. On the one hand it produces an Origen, on the other hand, an Arius.
And then, of course, a hero of mine, Maximus the Confessor, who's contribution is inestimable – he is the one who, in correcting the errors of Origen, in a stroke of illumined genius, flipped the triune axiomatic of the Platonists – 'stasis-kinesis-genesis' (stasis being 'rest' of souls coexisting with God;
kinesis is their impulse to movement (away from God),
genesis the passage of spiritual beings from the immaterial and intelligible to the bodily and sensible) on its head to render it '
genesis (‘coming into being’,
creatio ex nhihilo), kinesis is the natural and God-implanted inclination (
logos) of created beings to their creator, an impetus that conveys them from their point of origin to their final end – st
asis the rest in the eschaton, when creatures will become
by grace what God is
by nature, and thus participate in the Eternal as both Paul and the Johannine scribe hinted at in the verses cited above.