0.9$, $0.05 < \Omega_m < 0.45$, and $0.01 < \Omega_bh^2 < 0.03$. We then impose an age of the universe constraint by randomly sampling these models so that the age of the universe has a probability distribution whose shape is given by equation \[eq:kraussagecorr\], but offset by $0.3$ Gyr. We use the publicly available code [CMBFAST]{} [@SeljakZaldarriaga96] to compute the resulting distribution of $\ell_1$. This is shown in Figure 2 where the two solid lines are the 68% and 90% [*joint*]{} confidence levels.

As expected, the age alone does not constrain $w$; there is a degeneracy between $w$ and $\ell_1$. If we now use the [*observed*]{} position of the first acoustic peak as recently measured, in a model independent way, from [*WMAP*]{} [@PageWMAP03], we can constrain $w$ with high accuracy. The filled contours in Figure 2 are marginalized values for $w$ at the 68% and 90% confidence levels. Thus we find $w<-0.8$ ($w < -0.67$) at the 68% (90%) confidence level. If we drop the assumption that the oldest GC must have formed before reionization, but still impose that they must have formed by $z=6$, this constraint is slightly weakened. In this case the age distribution of equation \[eq:kraussagecorr\] needs 