Coming of the Andals

The eyes of the Andals had turned south, and longships had begun to come ashore all up and down his coasts, full of hungry men with the seven-pointed stars painted on their shields and chests and brows, all of them bent on carving out kingdoms of their own. 
- The World of Ice and Fire

The Coming of the Andals, also known as the Andal Invasions (or A.I. for dates), refers to the mass migration of Andals over the Narrow Sea from Andalos, their homeland in Essos, to Westeros. The Coming of the Andals is considered to mark the end of the Age of Heroes. Nonetheless, the Age of Heroes did not end all at once, nor did the Andals all set sail across the Narrow Sea as a single movement.

Earliest Andal Arrivals

The First Andals began to arrive in Westeros for up to two centuries prior to what is considered the beginning of the 'Andal Invasions' proper. These Andals tended to arrive in the form of mercenaries and traders. Early examples of Andal Houses that settled in Westeros from this period are the Lannisters of Casterly Rock, the Mallisters of Seagard, and the Hollards of Duskendale.

The manner of these Andals gaining land and position in Westeros - as it would continue to in later years - varies greatly. House Mallister offered their services to the Mudd Kings, ridding the Cape of Eagles of the Ironmen. In exchange, the Mudds established the Mallisters as lords on the Cape - one part gratitude, but another practicality, using the Andals as a shield against further incursions. The Hollards took service in the Household of the Darklyn Kings of Duskendale, and thus earned land and honours - even securing three marriages with the royal line, binding themselves in blood as well as vows to their First Men overlords. The Lannisters took a different path. Though the details are somewhat lost in the promulgation of tales and legends, it is clear enough that Lann, whoever he was, took service with Lord Casterly, and through means of trickery and manipulation, placed himself as the heir to their lands and fortunes. His Andal blood would then express itself through the introduction of new martial traditions, the urban expansion of Lannisport and the development of a defensive fleet, and by the desire to expand beyond the Casterly Lands to form a new kingdom.

What is particularly notable about these early Andals however - is that they lack the examples of zealotry and religious fervour found so often in the Andal Adventurers and would-be conquerors following 1 A.I. Whilst the Mallisters and Hollard's kept their faith - they never made focused efforts to press their faith on neighbouring lords, and the Lannisters appear to have put their faith in the Seven aside entirely in order to present themselves as more legitimate rulers of their growing kingdom. Why this is is open to conjecture, but will be further discussed.

The Andal 'Invasions'

Whilst the more gradual arrival of Andals to Westeros, often taking service or settling along the coasts of Blackwater Bay continued in the period following 1 A.I., it cannot be denied that there was a significant shift in the attitudes, objectives and numbers of Andals who began descending on Westeros at this time.