  A major paradigm shift has recently revolutionized our picture of globular
clusters (GC) that were long thought to be simple systems of coeval stars born
out of homogeneous material. Indeed, detailed abundance studies of GC
long-lived low-mass stars performed with 8-10m class telescopes, together with
high-precision photometry of Galactic GCs obtained with HST,have brought
compelling clues on the presence of multiple stellar populations in individual
GCs. These stellar subgroups can be recognized thanks to their different
chemical properties (more precisely by abundance differences in light elements
from carbon to aluminium; see Bragaglia, this volume) and by the appearance of
multimodal sequences in the colour-magnitude diagrams (see Piotto, this
volume). This has a severe impact on our understanding of the early evolution
of GCs, and in particular of the possible role that massive stars played in
shaping the intra-cluster medium (ICM) and in inducing secondary star
formation. Here we summarize the detailed timeline we have recently proposed
for the first 40 Myrs in the lifetime of a typical GC following the general
ideas of our so-called "Fast Rotating Massive stars scenario" (FRMS, Decressin
et al. 2007b) and taking into account the dynamics of interstellar bubbles
produced by stellar winds and supernovae. More details can be found in Krause
et al. (2012, 2013).
