The Western Schism
     "The schism in the western Church resulted from the return of the papacy to Rome under Gregory XI in 1376, ending the Avignon Papacy, which had developed a reputation of corruption that estranged major parts of Western Christendom. This reputation can be attributed to perceptions of predominant French influence and to the papal curia's efforts to extend its powers of patronage and increase its revenues.
     After Gregory XI died, the Romans rioted to ensure the election of a Roman for pope. The cardinals, fearing the crowds, elected a Neapolitan when no viable Roman candidates presented themselves. Pope Urban VI, born Bartolomeo Prignano, the Archbishop of Bari, was elected in 1378. Urban had been a respected administrator in the papal chancery at Avignon, but as pope he proved suspicious, overbearing, and prone to violent outbursts of temper. The cardinals who had elected him soon regretted their decision: the majority removed themselves from Rome to Anagni, where they elected Robert of Geneva as a rival pope on September 20 of the same year. Robert took the name Pope Clement VII and reestablished a papal court in Avignon. This second election threw the Church into turmoil. There had been antipopes - rival claimants to the papacy before, but most of them had been appointed by various rival factions; in this case, a single group of leaders of the Church had created both the pope and the antipope.
     The conflicts quickly escalated from a church problem to a diplomatic crisis that divided Europe. Secular leaders had to choose which claimant they would recognize."
Source: Catholic Encylopedia
PLATE # 14

The image in plate 14 at left has the bottom portion cut off, so I have added two additional versions at the bottom of this page. I'm beginning to think that someone very close to the various popes did these plate images - perhaps a bishop or cardinal - or the 'rooster'. I'm also wondering if a pope incorporated one-third of the 'holy' descendants into the church as cardinals - thus the use of birds in these images. It appears that a pope, or popes, took people from all 3 'divine' lines. These immoral popes probably produced children via the 'sacred' bloodline as well, expecting to have 'divine' descendants for their church - aren't they simply disgusting? For our consideration:
1) a pope,  2) a wolf's head  3) a rooster  4) a snake or serpent

The pope here is either Pope Gregory XII or Pope Martin V - popes that reigned during the years there was an anti-pope, plus there was a 2 year period with no pope at all - see chart below. The wolf head is Jan Hus [his article below]. The Rooster represents the one entitled to the 'keys to the kingdom'.
The Great Schism of Western Christianity, or Papal Schism (also known as the Western Schism), was a split within the Roman Catholic Church from 1378 to 1417. By its end, three men simultaneously claimed to be the true pope. Driven by politics rather than any real theological disagreement, the schism was ended by the Council of Constance (1414–1418). The simultaneous claims to the papal chair of four different men hurt the reputation of the office. The Western Schism is occasionally called the Great Schism, though this term is more often applied to the East-West Schism of 1054.

It seems the serpent is after the 'keys to the kingdom' too. This may indicate an anti-pope who was installed during the period of 1378 - 1449. There were 3 anti-popes during this time period, but it seems they are referring to John XXIII in this instance. The antepopes were installed via the church, but since the church was divided, one branch didn't recognize the other branch nor their pope.
1. Robert of Geneva (Clement VII), 20 September, 1378 to 16 September, 1394, classified as an anti-pope by Rome.
John XXIII (1370-1419), classified as an anti-pope by Rome.
3. Amadeus of Savoy (Felix V), November, 1439 to April, 1449, classified as an anti-pope by Rome.
The Council of Constance
In the Roman Catholic Church, the 'Council of Constance' is the 16th ecumenical council. It was held from 1414 to 1418. The council resolved the Western Schism in which three men simultaneously claimed to be pope. Furthermore, Jan Hus was condemned and executed during the council. In response to a controversy in Poland, the council ruled on issues of national sovereignty, the rights of pagans, and just war. The council represented a high point for the movement that promoted the authority of councils over the authority of the pope, but in the end the pope's authority was re-affirmed.
Jan Hus was a key contributor to the Protestant movement whose teachings had a strong influence on the states of Europe and on Martin Luther himself.The Roman Catholic Church considered the teachings of John Hus heretical; consequently Hus was excommunicated in 1411, condemned by the Council of Constance, and burned at the stake in 1415.
30 November 1406 - 4 July 1415 Pope
Gregory XII
Western Schism; abdicated during the Council of Constance, which had been called by his opponent John XXIII.
4 July 1415 - 11 November 1417 Interregnum
no pope
Two year period without a valid pope elected. Alexander V and John XXIII were both antipopes during this period.
11 November 1417 - 20 February 1431 Pope
Martin V
Convened the Council of Basel, 1431