What we think of as the modern discipline of history was born in the western 19th century. Historians always reflect the mores and concerns of their age. Both before and after Leopold von Ranke and his contemporaries, historians did not so much actively suppress women's lives so much as ignore them. This was for two reasons: (1) women were not seen as a worthy subject of study in their own right (2) the areas in which women tend to be historically visible were not considered worthy of study. Both of these things start to change in the 1960s in America, but only with the long, strenuous, and heroic efforts of scholars above all Gerda Lerner.

Medieval historiae or chronicles are more like records of events than the type of explanatory narrative we're familiar with today. Nevertheless, they already reflect the pattern of what the first modern historians will see as primarily relevant topics for historical inquiry: kings, thrones, city councils, calamities. These proto-historians, primarily monks and clerks, can't necessarily be accused of actively erasing women: they mention rulers' marriages, daughters' births, women prophets or saints who saved/false women saints who ruined a city. Orderic Vitalis even praises Adela of Blois, not even a ruler in her own right, for the care and skill with which she administered her county while her infamous husband was on crusade. It's just that in general, medieval women are not (...are systemically excluded from) leading armies and maneuvering to win papal elections and feuding aginst competing noble families.

Late medieval/early modern historians actually introduced a genre of "eminent women" texts (De claris mulieribus being the Latin form), recounting the stories of individual famous women throughout history. Or rather "history," as they tended to draw freely from mythology, legend, and their imaginations as well as the actual past. These texts could serve as a commentary on the state of men/male-dominated society of the time, be a salvo in an intellectual sparring match (the querelle des femmes), and/or represent a genuine interest in the subject matter. Nevertheless, it's still an isolation of women from the idea of a major, world history progression.

Enlightenment-era history and then the rise of modern history make leaps and bounds in narrative and historical method (modern history is marked by rigorous scrutiny of primary sources, above all). It remained dominated by political history, which until very very recently was the study of--yup--rulers and nations. Considering the actions of rulers and seeking to understand the course of events is an area of history in which men are, indeed, much more prominent than women.

Modern history is also born in universities and academics like to write about ourselves, so intellectual life--philosophy--also become a prominent area of study (Burckhardt, Haskins). While women certainly wrote philosophy, they are very rarely seen as groundbreaking. So Haskins in his Renaissance of the Twelfth Century will mention Herrad of Hohensburg's (although he says Landesburg) Hortus deliciarum with no qualms about it being the creation of a women's convent, but when it comes to philosophy power couple Heloise and Abelard, he delves extensively into Abelard's work (with good reason) but Heloise only gets a name-drop as Abelard's lover--not even a mention of her brainpower, because it didn't "shape history" like Abelard did.

Where women did tend to be prominent in medieval and early modern history was religion. Religious history in the 19th and early 20th centuries remained compartmentalized, typically the province of confessional (Catholic and Protestant) historians for the purposes of their own churches and congregations--it tends to be a lot more sentimental and devotional, stories of saints' lives meant to inspire prayer and piety. I don't want to undersell the work of especially turn of the 20th century Germans here. I study, among other things, a couple of really obscure medieval women, and literally the only published source devoted to one of them is the modern publication of her hagiography, with a scholarly (not devotional) explanatory article, from a German scholar in IIRC 1888! But religious history was not part of Real History, in general (the Germans sort of make an exception for the Reformation, although this is a really contentious piece of history at the time due to Catholic versus Protestant polemic).

In the 1960s, especially in America, two things were changing. First, historians like Gerda Lerner built on the work of some earlier pioneers like medievalists Lina Eckenstein and Eileen Power who made women a worthwhile subject of study in their own right. They argued and proved that understanding women's roles in society is crucial to understanding the past "as it really was," to quote von Ranke. Again, this development--both Lerner's fight and the ability of her and her comrades to carve a lasting foothold--reflects changing attitudes of time, obviously here second-wave feminism. Second, the rise of cultural history on the back of the social history movement especially after World War II brought enormous scholarly attention to areas of history where women indeed tend to be more visible: religion, literature, family life.

The situation isn't perfect today. On the academic level, the field of history is about 40% female. Go to a conference or pick up a volume on women, and the represented scholars are 95% female. There is still a strong trend in academia of compartmentalizing women's roles in history as women's history, although at least in medieval there are some amazing historians--at the top of the field, even--striving to change that, both male and female. And scholars are quite skilled at hunting for women in difficult sources, but sometimes the sources themselves are simply uncooperative.

Far more critically, IMHO, as teaching history inevitably means having to squeeze in more and more years each time pre-college textbooks are revised (time refuses to stop. I KNOW, right? Sheesh.), it's more and more tempting to just "hit the important parts"--which can so, so easily mean a return to narratives of rulers and nations. We want the story that got us here today, not understanding the texture of the past. (i.e. do the roots of 'human rights' as a concept in medieval political philosophy matter more for understanding the contemporary world than Clare of Assisi's struggle to establish a Franciscan Second Order for women? The problem is that the first roots of human rights in the western tradition are planted in and by a world that Chiara's struggle helps us understand, but how important is understanding in light of a looming AP Euro test?).

To make women visible in the historical narrative is an ongoing struggle. The sources are not always generous, and the work that we want the past to do does not always line up with the constraints that patriarchal societies places on women in the past and to a varying extent today. For centuries, historians did not see any real need to fight that battle--in fact, they weren't even aware there was a battle to be fought. Today, at least we're fighting. (ETA) The fact that threads about the absence of women from the telling of history can get double-digit upvotes on Reddit of all places is a hopeful sign.