I'm currently reading one of the books I was bought for Christmas, specifically A History of Pi by Peter Beckmann. It is a really interesting book and I've learnt all sorts of weird things.
One of the stranger things I learnt this morning was that Cartesian geometry is actually named after René Descartes. I was baffled by this statement until I read the next sentence that points out that he latinized his name to Renatus Cartesius. Well that explains everything then!