Economic Growth Through the Middle Ages

I don't know much about this, but it's a very interesting question and I wanted to share this link
http://www.netserf.org/History/Economic/
which you probably found yourself but just in case you didn't, it seems to link to a lot of information, although it doesn't seem to be summarised at all.

My own feeling is that in the post Roman Europe, one made money through conquest, which is much closer to a zero-sum game than free enterprise is. If you study the history of a single European state, its fortunes will rise and fall but the overall economic growth of europe was probably fairly static and low.
The very wealthy/nobility class would invest heavily in fortifications and military technology (Europe's arms race lead directly to the technological breakthroughs of the industrial revolution); but probably not so much in other sorts of enterprise.
Things did generally improve over the thousand years before Columbus opened up the Americas (which roughly coincided with the renaissance, which is obviously responsible for accelerating development too), but progress made over the following 500 years seriously dwarfed it.
(The poor state of Europe just prior to the renaissance has been over-emphasised -- mostly by the renaissance-era historians whose descriptions of the Gothic period are analogous to us laughing at our parents' clothes).

I would guess that there's a fairly constant rate at which people find better ways to organize themselves and their surroundings to improve economic output. But in most times and places the counterbalance to that is political instability. They fought a lot of wars in the Middle Ages, and those were very destructive. I think that the subsequent success of Europe is mostly the story of limiting wars in both scope and intensity.

That also explains why Europe did so well when other regions didn't. Europe had its peculiar power balance between the Pope and the kings. This prevented any one ruler from amassing enough power to make a bid for total control.

mauyr: Yeah, there is a lot of data out there, but hasn't anyone tried to aggregate it? If so, I can't find it, even an educated guess.

BB: Yeah, I think wars are typically a negative-sum game, especially when they compound on each other rather than lead to enhanced stability.

This paper claims standarization of language and advances in contracts fueled economic growth, and that there is no reliable data about per-capita income from the period.

How did the economy of Western Europe perform over the last five centuries of the Middle Ages? Maddison's (2001, 264) estimates of per-capita income for present-day European countries in 1500 are measured on the horizontal axis of Figure 1.9 There is a considerable gap between the poorest country, Portugal, and the richest, Italy; however, all countries had income levels greater than $600 in 1990 international dollars. The latter figure is perhaps 50 per cent higher than the subsistence level (Maddison, 2001, 260). As the vertical axis shows, those countries with the highest income levels -- Italy and Belgium -- were also the most highly urbanized in the latter year.10 Unfortunately, there are no reliable estimates of per-capita income by individual country for the period before 1500. However, it is generally agreed that on the whole income levels at the turn of the millennium were close to the subsistence level. Urbanization rates at that time were also low. We therefore suggest that urban growth rates might be used as a proxy for rates of increase in per-capita income in the years before 1500.