The period of peace which followed the Hundred Years War continued in Champagne until the beginning of the sixteenth century. Under Louis XII and François I  the kingdom of France was again at war, but military operations generally only involved the outskirts of the region, and calm continued to reign in the wine-producing areas. However in 1544 the first signs of danger appeared: the troops of Charles Quint burnt Vitry and descended the Marne Valley as far as Château-Thierry. François I found himself obliged to burn Epernay in order not to let the supplies that were stored there fall into the hands of the enemy.
From 1562 the religious wars brought violence and disorder to the entire region. In 1563 the abbey of Hautvillers was destroyed and the monks had to take shelter in Rheims where they remained for forty years. Lutheranism arrived early in Champagne, especially in Troyes, Châlons, Sézanne, and even in Rheims, which was the stronghold of the archbishops of the Guise  family and the Holy League. Even though the campaigns were harsh the vineyard towns did not suffer very much. Epernay, remaining resolutely Catholic, was however the site of fierce fighting in 1586 and in the following years. In 1592 Henri IV came in person to lay siege to the town, held by the soldiers of the League, and had the misfortune to see his friend the Marshall of Biron killed by a cannonball by his side. Here is what Philippe-Valentin Bertin du Rocheret wrote in his Ouvres Measles :
During the siege of Epernay, which began on 24 July 1592, the army of King Henri IV was camped at Choüilly, the Prince going often to Damery to visit the President of Puy who lived there in her Vendangeoir... One day he was coming back at a slow gallop and the wind blew off his hat as he reached the road from the suburb of Igny. The Maréchal of Biron picked it up and put it in jest on his own head, the white plume that decorated it caught the eye of Petit, the head gunner of the town, who, aiming at the white plume said to his comrades: "To the King!" And indeed pointing his cannon, known as the Dog of Orleans, he blew off the the Maréchal’s head on 4 August 1592.
Champagne again sank into misery. Claude Haton, the curate of a parish in the Aube, wrote, "One cannot believe the suffering that the poor people of the villages have endured, not just physically, but also in their minds and souls, and in terms of their belongings, their livestock, and other things, men and women equally, and at the hands of their own people". Jean Pussot, a master carpenter of Rheims and owner of vines, noted in his Journalier in 1592, "The troubles continue, except for a short truce that was made with those of Chalons for the taking in of the harvest and transporting of the wines." And then later, "In this time there is another affliction, which is that the wolves have become so fearless that they have leapt upon and devoured several people, not only in the fields but in the vines and villages." The plague struck in 1598 but the same year also finally brought the promise of peace and tranquillity after half a century of misery, the Treaty of Vervins was signed by Philippe II of Spain and Henri IV, who was to enter Rheims in 1606.
Vineyards suffered greatly during this period, but did nevertheless continue to produce wine, sell wine, and even to give wine! For it was customary in those times to offer important people the vins de ville (the town’s wines) , as a sign of respect, and to obtain their protection or to honour them during their visit. As an example from amongst thousands, the minutes of an assembly of the town of Epernay on 25 May 1540, records a gift of twenty poinçons  of wine to the Seigneur de Guise.
During these difficult years commerce was obviously hindered by the poor condition of the roads and the presence of various warring parties, even though the latter were sometimes good customers. According to Pussot in 1579, wines which had been frozen were rarely good, and were only worth VII L a "queue" .
However it was not entirely impossible to trade with the enemy, as demonstrated by a "placcart" published by Philippe IV, the King of Spain, in Brussels, permitting "on a trial basis, and with provisional tolerance for the year of the last harvest, the entry of the wines of Ay or Charroy from enemy territory, without the requirement of another licence, or special passport" . The places of entry listed were Cambrai, Valenciennes, Avesnes, Philippeville, Marienbourg, Luxembourg, Montmédy, Givet, and the authorization applied to those transporting by the Meuze River, and to merchants or enemy carriers. Indeed, export had become a common practice, and we know for example that Brother Geoffroy Piérard, procurator of the abbey of Saint-Martin of Epernay, sold in 1561 to a merchant from Liège forty " poinssons" of claret wine for the price of twenty one pounds a queue .
It was the peace at Vervins that marked the renewal of the growth in Champagne’s production of wines. These were still only known by the name of their cru (vineyard), or by the expression vins de Rivière, if the need arose, or by the name of the city where they were sold, as in the vins de Rheims . The term vins de Champagne did not appear until around 1600 , and did not become commonly used until the second half of the seventeenth century. Their reputation was established slowly, as we saw in the study of the wines served at the coronations of the kings of France, and Dom Chastelain reflects the general optimism when he wrote in the eighteenth century, Under François I and Henri II the wine of Reims took favor everywhere . In the Maison Rustique (200), a farming manual that appeared in 1586, wine-producing areas are listed several times, from chapter V onwards of book VI. Thus we find Beaune, which comes as no surprise, Rochelle (La Rochelle), Bourdeaux, Chabyles (Chablis), Tonnerrois, Auxerrois, Angevin, Languedoc, and Provence. But it is only in chapter XXII that a name from Champagne finally appears, The wines of Ay, being less vinous than these , are also salubrious beyond comparison. And then further on we are told that the wines of Ay are claret and tawny coloured, subtle, delicate and of a very agreeable flavour, and for these reasons are desired for the mouths of Kings, Princes and great Lords. The author of the Maison Rustique does however declare that his personal preference is for the wines of Burgundy, rather than those of Orléans and Ay, which are so appreciated in Paris.
All of this suggests that, at the end of the sixteenth century, the wines of the Champagne region were still comparatively little known, although the wines of Ay would seem to have gained a certain reputation. In 1601 Nicolas Abraham de la Framboisière produced a new version of the Maison Rustique, and concluded in his treatise in the chapter devoted to wines:
To judge the character and quality of a wine one must look carefully at the state and constitution of each year, and taste it every year in order to pass a sound judgement. Some years the wines of Burgundy take the prize; in other years the wines of Orleans surpass all; in no years are the wines of Anjou more excellent than all the others; and most often the wines of Ay hold first place in quality and perfection.
This reputation can in fact be traced back to the beginning of the sixteenth century: in 1518 Admiral de Bonnivet wrote to his friend Cardinal Wolsey, the Chancellor of England, to tell him that twenty poinssons of Ay wine had just been sent to him. There is even earlier evidence if we are to believe the story according to which in 1410 Sigismond of Luxembourg, the King of Hungary and future Emperor of Germany, made a detour during a journey through France in order to taste the wines of Ay.
It is often supposed that kings and even popes, had vendangeoirs ("harvest houses") in Ay, where an old half-timbered house is presented as having been that of Henri IV (see illustration below). Despite the links between the Vert-Galant (one of Henri IV’s nicknames meaning "the indefatigable romantic") and Jurançon (as a baby his grandfather is said to have moistened his lips with the wine of Jurançon) one might think that his popularity would be well matched with that of the wines of Ay. From which must come the anecdote that appears in the foreword of an Anthology of Latin and French Poems on the Wines of Champagne and Burgundy that was published in 1712. The occasion was the reception of the ambassador of Spain by Henri IV. The ambassador referring to his own king as the king of all the kingdoms that make up the Monarchy of Spain, and listing them one after the other, without omitting a single one, "You will say," Henri IV interrupted him, "to the King of Spain, of Arragon, of Castille, of Leon, etc., that Henry, King of Gonesse and Ay, replies...." The good King setting against all the kingdoms of the King of Spain only those of Good Bread and Good Wine. The anecdote was repeated in a slightly different form in the Mercure de France in January 1728.
Like Henri IV, Saint-Evremond  appreciated the wines of Ay. He wrote the following in a letter that he sent towards the end of 1674, to the Count of Olonne who had just been exiled in his country:
Adjust your tastes to your health as much as you can. Spare no expense in order to have the wines of Champagne, you need go but two hundred leagues from Paris. If you ask me which of these wines I prefer then, without indulging in attempts at pretentious refinement, I would say that the Ay wine is the most natural of all the wines  , and the most wholesome, it has a purity that transcends the earthiness of other wines, and an exquisite peach flavour that adds greatly to its charm, and in my opinion accounts for its unique character. Léon X, Charles Quint , Franfois I, and Henry VIII21, all had their own houses in or near Ay, in order to control their supplies more closely. And so among all the important matters that these great kings had to deal with, having the wine of Ay on their tables cannot have been the least of their worries. 
Sutaine, in his Essai sur l’histoire des vins de Champagne, expresses more or less the same views and notes that there still exists an area called "le Léon", probably after its former owner Léon X . It is possible that there were harvest houses belonging to the sovereigns of the Renaissance, but it is more likely that they contented themselves with employing and lodging their own pourvoyeurs (purveyors) who would then supply them with the vins de Rivière. There is no doubt that from the sixteenth century onwards the vineyards of Ay were producing excellent wines. It is less certain that the term vins d’Ay included other wines of the Rivière region, which would have not only been a great credit to any such wines, but also to their advantage because they would have benefited from Ay’s reputation and commercial value, which was substantial at that time.
 During the reign of François I the Earldom of Champagne was replaced by the military government of Champagne and Brie, seated in Troyes, and including the ecclesiastical domains of Rheims, Châlons and Langres. The Généralité de Champagne, an administrative body based in Châlons,.was created within the government in 1542.
 It was in Dormans that the Duke of Guise, Head of the Holy League, was wounded in 1575 with a harquebus (an early type of gun) giving him a scar that earned him the nickname of le Balafré.
 The date is wrong and the story has been slightly embellished. Here is what Henri IV wrote to his ambassador in London, Monsieur de Beauvoir, on 10 July 1592 : Yesterday, being lodged in the town of Damery, and wanting to ride after supper, to go along the river, from the other side of Espernay, and recognizing the dangers, my cousin the Maréchal de Biron, against my wishes, wanted to come with me, it so happened that a piece of small shot fired from the town did strike his head and he died within the hour, misfortune came only to him, and nobody else in the troop was injured.. The President of Puy, mentioned by Bertin du Rocheret was Anne Dudley, wife of Oudart of Puy, President of the Election of Epernay; Henri IV called her his belle hôtesse (Mercure de France, January 1728).
 The "vin de ville" was wine that the officers of the town offered as a gift to certain worthy people (Grand Vocabulaire français).
 A poinçon varied between 180 and 250 litres.
 A queue was about 400 litres.at Christmas. The camp in front of the Fère took them for XV L a queue [[PUSSOT (Jean). Journal or Memoirs of Jean Pussot, master-carpenter in the Couture of Rheims, published by E. Henry and Ch. Loriquet. Rheims, 1858.
 Placard of the King our Lord on the entry of the wines of Ay and others of Charroy. Brussels, 1643.
 Bulletin from the Experimental Laboratory of Wine Production and Oenology of the Maison of Moët & Chandon. Epernay, 1908.
 The name of the city of coronations was spelled Rheims in the Middle Ages, or sometimes Raïns, Rainz, or Reins. At the start of the seventeenth century the modern French spelling of Reims first appeared, and was used alongside Rheims until the beginning of the nineteenth century (in the Le Grand Vocabulaire François of 1769, there is: Reims, see Rheims). In some countries, in particular the Anglo-Saxon ones, the old spelling of Rheims has been retained, which is why it is today often to be found on bottles of champagne destined for the export market.
 DION (Roger). History of the Vine and Wine in France up to the Nineteenth Century - Paris, 1959.
 JADART (Henri). Journal of Dom Pierre Chastelain, Benedictine monk in Rheims 1709-1782 with his Remarks on the temperature of vines, followed by another journal with similar observations up to 1848. Rheims, 1902.
 these refers to the wines of Gascony.
 Charles de Marguetel de Saint-Denis de Saint-Evremond, 1614(?)-1703, soldier, essayist, epicurean philosopher, exiled to England in 1662, and well-known for his wit, wrote to Saint-Simon that, his works and his constant love for Madame de Mazarin, would keep him in England until he ended his days in extreme old age.
 Curiously we find here an echo of the advice given to Hincmar by Pardule in the ninth century (cf. The Early Middle Ages).
 In 1538, for the reception of Marie of Hungary, the sister of Charles Quint, the sum of five hundred pounds was recorded for the purchase of the wine of Ay. The Mercure de France of January 1728 reports that during the Siege of Epernay in 1544, Charles Quint was camped at Avenay, and his quarters were above Ay, in a harvest house that was built for him and which today still bears the name of Charlefontaine.
 Saint-Evremond. Works of Monsieur de Saint-Evremond, and the Life of the Author, published by Des Maizeaux. Amsterdam, 1726.
 Léon is between Dizy and Ay, immediately to the south of the D1 road; not to be confused, as certain authors have done, with the slopes to the north of the road, which bear the less noble name of Froid-cul (Cold Bottom).