So, Henry II is certainly an interesting figure with a number of known mistresses and a, shall we say, tumultuous relationship with his wife and sons. In the specific case of Alys of France, academia seems to have accepted that Henry II certainly might have taken advantage of the situation (Slater, 2012; Hilton 2010; Hilliam, 2004), but it's interesting to see where some of the specific allegations arise.

One of the most significant sources for Henry's impropriety is Gerald of Wales' De instructione principum, commonly known in English as How to Bring up a Prince. Far be it for me to call Gerald a liar, but he is a man with several large axes to grind. Gerald's career is underlined throughout by his relentless self-promotion and his open hunger to become Bishop of St David's, and his steadily growing frustration and resentment at not being given the job. Many of Gerald's works serve in some way to promote either his interests, or those of his family, and his forewords and dedications provide some very interesting reading. One of Gerald's particular axes is the promotion and justification of his family's actions in the 1172/3 conquest of Ireland; his Topographia Hibernica is littered with some frankly extremely fanciful episodes which serve to emphasise the bestial and savage nature of the Irish and how badly they need the Cambro-Norman civilising mission. He also conveniently chronicles Diarmait Mac Murchada promising land to Robert de Barry to legitimise the latter's conquest of South Munster, and happens to be the only source for the 1172 Synod of Cashel where the Irish clergy conveniently agree to be subservient to the English church in all matters. What I'm driving at with this digression is that, while Gerald is broadly speaking a useful and informative source, he is also extremely partisan, and you need to be particularly careful when he has an agenda to push.

Although he alludes to writing it for some time, Gerald's De instructione principum doesn't appear until 1216, when his chances of achieving the bishopric of St David's had well and truly passed, and his relationship with the Angevin kings had turned extremely sour. Gerald had briefly even been put on trial in 1202 for stirring up dissent among the Welsh, and had gone so far to write a bitter letter of complaint to Pope Innocent III about his supposed mistreatment. You can trace his growing discontent with the Angevins through the dedications to his successive works and reissues. In the c.1185-8 dedication of his Topographia Hibernica to Henry II, (notably at the time when Henry would be active with Alys), Gerald praises the "invincible king" and "high-minded prince [who] would place little value on things that easily come to be." In stark contrast, the 1214 dedication of Gerald's Itinerarium Cambriae (which first appeared in 1195), when both Henry II and Richard I were safely in the ground, complains that he "completely wasted his time" in dedicating successive versions of the Topographia to Henry II and "his son and successor in vice" Richard, saying that "both these princes had little or no interest in literature and were much preoccupied with other matters." The 1214 edition of the Itinerarium Cambriae and the forthcoming De instructione principum were at this juncture dedicated to Archbishop Stephen of Canterbury, with the somewhat snotty proviso that "you accept the charge of actually reading it when you have the time" and the audacious argument that if Stephen doesn't read it or "if perchance I fail to please you... then, indeed, the esteem in which literature once was held really has vanished."

The De instructione principum when it does appear in 1216 is essentially an extended hatchet-job on the entire Angevin dynasty. After a foreword condemning the offence given to the Church by Henry II, his obstinacy and tyranny, Gerald spends almost the entire first "distinction" of his work praising the various qualities of Henry's rival Louis VII, his moderation, gentleness, patience, temperance, clemency, munificence, prudence and other fine values. In contrast, the second and third "distinctions" deal with such issues as:

2.3: [Henry's] later crimes and the martyrdom of Thomas Becket.

2.7: The three monasteries promised in compensation for the failed pilgrimage, and how the promise was evaded

2.12: God's warnings to Henry II and how they were ignored

3.11: Henry II's confusion and anger

3.13: King Henry II's groin trouble and his late and forced confession

3.27: The unfavourable family background of Henry II and Queen Eleanor of Aquitaine and of their children

It's also worth noting that another of the sources for Alys having borne Henry's illegitimate child is the Chronica monasterii de Melsa, which wasn't compiled until the late C14th, although presumably from earlier sources, and that Meaux Abbey's founder, William le Gros, himself had some disputes with Henry II, being forced to cede Scarborough Castle to him.

While none of this should serve to say that the rumours surrounding Henry II and Alys are definitely untrue, it should definitely be noted that, especially in the case of Gerald of Wales, they come from sources that are very much partisan, and very much have an agenda stemming from long-standing bitterness towards the Angevin dynasty.