# Relation between Bayesian analysis and Bayesian hierarchical analysis?

I have been studying a Bayesian hierarchical model. In that model all I am dealing is with the estimation of parameters. In Bayesian analysis, loosely speaking, we update our prior knowledge (in light of new evidences/data) to posterior knowledge. But in hierarchical model I don't see any prior knowledge or any prior distribution.

My question is what is the relation between Bayesian analysis and Bayesian hierarchical analysis?

I suppose the latter is a subset of former but I am still confused how are these two related? Is it enough for any statistical model which uses Bayes theorem to be categorized under Bayesian analysis/statistics?