Context : Reconstructing the structure and history of young clusters is pivotal to understanding the mechanisms and timescales of early stellar evolution and planet formation .
Recent studies suggest that star clusters often exhibit a hierarchical structure , possibly resulting from several star formation episodes occurring sequentially rather than a monolithic cloud collapse .

Aims : We aim to explore the structure of the open cluster and star-forming region NGC 2264 ( \sim 3 Myr ) , which is one of the youngest , richest and most accessible star clusters in the local spiral arm of our Galaxy ; we link the spatial distribution of cluster members to other stellar properties such as age and evolutionary stage to probe the star formation history within the region .

Methods : We combined spectroscopic data obtained as part of the Gaia -ESO Survey ( GES ) with multi-wavelength photometric data from the Coordinated Synoptic Investigation of NGC 2264 ( CSI 2264 ) campaign .
We examined a sample of 655 cluster members , with masses between 0.2 and 1.8 M _ { \odot } and including both disk-bearing and disk-free young stars .
We used T _ { \mathrm { eff } } estimates from GES and g,r,i photometry from CSI 2264 to derive individual extinction and stellar parameters .

Results : We find a significant age spread of 4–5 Myr among cluster members .
Disk-bearing objects are statistically associated with younger isochronal ages than disk-free sources .
The cluster has a hierarchical structure , with two main blocks along its latitudinal extension .
The northern half develops around the O-type binary star S Mon ; the southern half , close to the tip of the Cone Nebula , contains the most embedded regions of NGC 2264 , populated mainly by objects with disks and ongoing accretion .
The median ages of objects at different locations within the cluster , and the spatial distribution of disked and non-disked sources , suggest that star formation began in the north of the cluster , over 5 Myr ago , and was ignited in its southern region a few Myr later .
Star formation is likely still ongoing in the most embedded regions of the cluster , while the outer regions host a widespread population of more evolved objects ; these may be the result of an earlier star formation episode followed by outward migration on timescales of a few Myr .
We find a detectable lag between the typical age of disk-bearing objects and that of accreting objects in the inner regions of NGC 2264 : the first tend to be older than the second , but younger than disk-free sources at similar locations within the cluster .
This supports earlier findings that the characteristic timescales of disk accretion are shorter than those of disk dispersal , and smaller than the average age of NGC 2264 ( i.e. , \lesssim 3 Myr ) .
At the same time , we note that disks in the north of the cluster tend to be shorter-lived ( \sim 2.5 Myr ) than elsewhere ; this may reflect the impact of massive stars within the region ( notably S Mon ) , that trigger rapid disk dispersal .

Conclusions : Our results , consistent with earlier studies on NGC 2264 and other young clusters , support the idea of a star formation process that takes place sequentially over a prolonged span in a given region .
A complete understanding of the dynamics of formation and evolution of star clusters requires accurate astrometric and kinematic characterization of its population ; significant advance in this field is foreseen in the upcoming years thanks to the ongoing Gaia mission , coupled with extensive ground-based surveys like GES .