The Creation of Bitcoin......Satoshi said he started working on it in 2007 
Nick Szabo: (assuming Nakamoto is not really Finney or Dai) ..Only Finney (RPOW) and Nakamoto were motivated enough to actually implement such a scheme.
There seems to be one other person with the motivation that Szabo says would be needed to create Bitcoin:
2007
Zooko quote: I want to invent something else: a truly decentralized economic mechanism. Research that points in this direction includes the sub-field of algorithmic mechanism design within economic game theory, some peer-to-peer research such as GNUnet, Wei Dais and Nick Szabos ideas about bit gold, Nick Szabos smart contracts, and much more. Another inspiration is BitTorrents tit-for-tat mechanism, which is decentralized and minimal, but gets the job done within its limited problem domain.
https://tahoe-lafs.org/pipermail/tahoe-dev/2007-June/000022.html
2007 Szabo applies BitGold(w/RPOW) and his Scarce Object theory to Zookos p2p hard drive node project with "Nanobarter" (THIS COMBINATION CREATES BITCOIN)
Szabo: One possible answer to central mint vulnerability is bit gold a currency the value of which does not depend on any particular trusted third party. Another alternative is (an object barter economyScarce Objects).
http://web.archive.org/web/20070625154046/http://unenumerated.blogspot.com/
http://web.archive.org/web/20070618142414/http://szabo.best.vwh.net/scarce.html
2007 Szabo's "Nanobarter" (READ THIS LINK)
http://unenumerated.blogspot.com/2007/06/nanobarter.html?m= 1
2007/2008 Zooko c++
https://tahoe-lafs.org/trac/pycryptopp/ticket/3
Quoted all this from:
https://bitcointalk.org/index.php?topic=857604.msg9583780#msg9583780
Nick Szabo: (assuming Nakamoto is not really Finney or Dai) ..Only Finney (RPOW) and Nakamoto were motivated enough to actually implement such a scheme.
There seems to be one other person with the motivation that Szabo says would be needed to create Bitcoin:
2007
Zooko quote: I want to invent something else: a truly decentralized economic mechanism. Research that points in this direction includes the sub-field of algorithmic mechanism design within economic game theory, some peer-to-peer research such as GNUnet, Wei Dais and Nick Szabos ideas about bit gold, Nick Szabos smart contracts, and much more. Another inspiration is BitTorrents tit-for-tat mechanism, which is decentralized and minimal, but gets the job done within its limited problem domain.
https://tahoe-lafs.org/pipermail/tahoe-dev/2007-June/000022.html
2007 Szabo applies BitGold(w/RPOW) and his Scarce Object theory to Zookos p2p hard drive node project with "Nanobarter" (THIS COMBINATION CREATES BITCOIN)
Szabo: One possible answer to central mint vulnerability is bit gold a currency the value of which does not depend on any particular trusted third party. Another alternative is (an object barter economyScarce Objects).
http://web.archive.org/web/20070625154046/http://unenumerated.blogspot.com/
http://web.archive.org/web/20070618142414/http://szabo.best.vwh.net/scarce.html
2007 Szabo's "Nanobarter" (READ THIS LINK)
http://unenumerated.blogspot.com/2007/06/nanobarter.html?m= 1
2007/2008 Zooko c++
https://tahoe-lafs.org/trac/pycryptopp/ticket/3
Quoted all this from:
https://bitcointalk.org/index.php?topic=857604.msg9583780#msg9583780