On 18 Oct 1319 [her grandfather] William Montagu 2nd Baron Montagu (age 44) died at Gascony [Map]. His son [her father] William Montagu 1st Earl Salisbury (age 18) succeeded 3rd Baron Montagu.
Around 1320 [her father] William Montagu 1st Earl Salisbury (age 19) and [her mother] Catherine Grandison Countess of Salisbury 1304-1349 (age 16) were married. She by marriage Baroness Montagu.
On 29 Nov 1330 Roger Mortimer 1st Earl March (age 43) was hanged naked at Tyburn [Map] accused of assuming royal power and of various other high misdemeanours. His body hung at the gallows for two days and nights. He was buried at Christ Church Greyfriars [Map]. Isabella of France Queen Consort England (age 35) subsequently requested his burial at Wigmore Abbey [Map] and, after firstly refusing, King Edward III of England (age 18) allowed his remains to be removed to Wigmore Abbey [Map]. His grandson [her future husband] Roger Mortimer 2nd Earl March (age 2) succeeded 2nd Earl March, 4th Baron Mortimer of Wigmore.
In 1332 Philippa Montagu Countess March was born to William Montagu 1st Earl Salisbury (age 31) and Catherine Grandison Countess of Salisbury 1304-1349 (age 28).
In 1337 King Edward III of England (age 24) created a number of new Earldom's probably in preparation for his forthcoming war against France ...
[her father] William Montagu 1st Earl Salisbury (age 36) was created 1st Earl Salisbury. [her mother] Catherine Grandison Countess of Salisbury 1304-1349 (age 33) by marriage Countess Salisbury.
William Bohun 1st Earl of Northampton (age 27) was created 1st Earl of Northampton. [her future mother-in-law] Elizabeth Badlesmere Countess Northampton (age 24) by marriage Countess of Northampton.
Hugh Audley 1st Earl Gloucester (age 46) was created 1st Earl Gloucester probably as compensation for his daughter Margaret Audley Countess Stafford (age 19) having been abducted by Ralph Stafford 1st Earl Stafford (age 35).
Robert Ufford 1st Earl Suffolk (age 38) was created 1st Earl Suffolk. (age 51) by marriage Countess Suffolk.
On 11 Jun 1349 [her father] William Montagu 1st Earl Salisbury (age 48) died. His son [her brother] William Montagu 2nd Earl Salisbury (age 20) succeeded 2nd Earl Salisbury, 4th Baron Montagu. Joan "Fair Maid of Kent" Princess Wales (age 20) by marriage Countess Salisbury.
On 23 Nov 1349 [her mother] Catherine Grandison Countess of Salisbury 1304-1349 (age 45) died at Bisham Abbey [Map].
Before 1352 Roger Mortimer 2nd Earl March (age 23) and Philippa Montagu Countess March (age 19) were married. She by marriage Countess March. She the daughter of William Montagu 1st Earl Salisbury and Catherine Grandison Countess of Salisbury 1304-1349. He the son of Edmund Mortimer and Elizabeth Badlesmere Countess Northampton (age 38). He a great x 5 grandson of King Henry "Curtmantle" II of England.
In 1352 [her daughter] Margaret Mortimer was born to [her husband] Roger Mortimer 2nd Earl March (age 23) and Philippa Montagu Countess March (age 20) at Wigmore, Herefordshire [Map].
On 01 Feb 1352 [her son] Edmund Mortimer 3rd Earl March, Earl Ulster 1352-1381 was born to [her husband] Roger Mortimer 2nd Earl March (age 23) and Philippa Montagu Countess March (age 20).
In 1359 [her daughter] Janet Mortimer was born to [her husband] Roger Mortimer 2nd Earl March (age 30) and Philippa Montagu Countess March (age 27).
On 26 Feb 1360 [her husband] Roger Mortimer 2nd Earl March (age 31) died. He was buried at Wigmore Abbey [Map]. His son [her son] Edmund Mortimer 3rd Earl March, Earl Ulster 1352-1381 (age 8) succeeded 3rd Earl March, 5th Baron Mortimer of Wigmore.
On 24 Aug 1369 [her son] Edmund Mortimer 3rd Earl March, Earl Ulster 1352-1381 (age 17) and [her daughter-in-law] Philippa Plantagenet Countess March 5th Countess Ulster (age 14) were married at Reading Abbey [Map]. She by marriage Countess March. He by marriage Earl Ulster. She the daughter of Lionel Plantagenet 1st Duke of Clarence and Elizabeth Burgh Duchess of Clarence. He the son of Roger Mortimer 2nd Earl March and Philippa Montagu Countess March 1332-1381 (age 37). They were fourth cousins. She a granddaughter of King Edward III of England. 
In 1381 Philippa Montagu Countess March (age 49) died.
[her son] Roger Mortimer was born to Roger Mortimer 2nd Earl March and Philippa Montagu Countess March.
Paternal Family Tree: Montagu
Maternal Family Tree: Sibylla Tregoz Baroness Grandison
King Richard III of England x 1
Elizabeth York Queen Consort England x 1
Margaret Tudor Queen Scotland x 1
King Henry VIII of England and Ireland x 1
Mary Tudor Queen Consort France x 1
Queen Mary I of England and Ireland x 1
Queen Elizabeth I of England and Ireland x 1
Jane "Nine Days Queen" Grey I Queen England and Ireland x 1
King Edward VI of England and Ireland x 2
King James I of England and Ireland and VI of Scotland x 2
Princess Elizabeth Stewart Queen Bohemia x 2
King Charles I of England, Scotland and Ireland x 2
King Charles II of England Scotland and Ireland x 2
King James II of England Scotland and Ireland x 2
King William III of England, Scotland and Ireland x 2
Charles Palatinate Simmern II Elector Palatine Rhine 1651-1685 x 2
King George I of Great Britain and Ireland x 2
Marie Louise Bourbon Queen Consort Spain 1662-1689 x 2
Mary Stewart II Queen England Scotland and Ireland x 2
Queen Anne of England Scotland and Ireland x 2
Sophia Charlotte Hanover Queen Consort Prussia 1668-1705 x 2
Anne Marie Bourbon Queen Consort Sardinia 1669-1728 x 2
King George II of Great Britain and Ireland x 2
Sophia Dorothea Hanover Queen Consort Prussia 1687-1757 x 2
Frederick William "Soldier King" I King Prussia 1688-1740 x 2
Charles Emmanuel III King Sardinia x 2
Louis I King Spain 1707-1724 x 2
Louise Élisabeth Bourbon Queen Consort Spain 1709-1742 x 2
Elisabeth Therese Lorraine Queen Consort Sardinia 1711-1741 x 2
Frederick "The Great" I King Prussia 1712-1786 x 4
Ferdinand VI King Spain 1713-1759 x 2
Louise Hanover Queen Consort Denmark and Norway 1724-1751 x 2
Victor Amadeus III King Sardinia 1726-1796 x 2
King George III of Great Britain and Ireland x 2
Frederick William II King Prussia 1744-1797 x 4
Queen Sophia of Sweden 1746-1813 x 2
Electress Wilhelmina Caroline Oldenburg x 2
Charles XIII King Sweden 1748-1818 x 4
Christian VII King Denmark and Norway 1749-1808 x 2
Caroline Matilda Hanover Queen Consort Denmark and Norway 1751-1775 x 2
Louis XVIII King France 1755-1824 x 4
King Charles X of France 1757-1836 x 4
King George IV of Great Britain and Ireland x 2
King William IV of the United Kingdom x 2
Marie Sophie Hesse-Kassel Queen Consort Denmark and Norway 1767-1852 x 4
Frederick VI King Denmark and Norway 1768-1839 x 4
Caroline of Brunswick Queen Consort England x 2
Frederick William II King Prussia 1770-1840 x 4
Ernest Augustus King Hanover x 2
King Louis Philippe I of France x 2
Louis XVII King France 1785-1795 x 4
Frederick William IV King Prussia 1795-1861 x 4
Caroline Amalie Oldenburg Queen Norway 1796-1881 x 4
William I King Prussia 1797-1888 x 4
Maria Christina of the Two Sicilies Queen Consort Spain 1806-1878 x 4
Queen Louise Hesse-Kassel of Denmark 1817-1898 x 2
King Christian IX of Denmark 1818-1906 x 4
Queen Victoria of the United Kingdom x 2
George V King Hanover 1819-1878 x 2
Frederick III King Prussia x 4
Victoria Empress Germany Queen Consort Prussia x 2
King Edward VII of the United Kingdom x 2
Frederick VIII King Denmark 1843-1912 x 6
Alexandra Glücksburg Queen Consort England x 6
George I King Greece 1845-1913 x 6
Gustav V King Sweden 1858-1950 x 8
Maria de las Mercedes Unknown Queen Consort Spain 1860-1878 x 4
George V King United Kingdom x 8
Victoria Mary Teck Queen Consort England x 6
Frederick Charles I King Finland 1868-1940 x 2
Constantine I King Greece x 14
Maud Windsor Queen Consort Norway x 8
Christian X King Denmark 1870-1947 x 6
Alexandrine Mecklenburg-Schwerin Queen Consort Denmark 1879-1952 x 8
Gustaf Adolph VI King Sweden 1882-1973 x 8
Alfonso XIII King Spain 1886-1941 x 8
Victoria Eugénie Mountbatten Queen Consort Spain 1887-1969 x 2
Louise Mountbatten Queen Consort Sweden x 2
Alexander I King Greece 1893-1920 x 20
King Edward VIII of the United Kingdom x 14
King George VI of the United Kingdom x 14
Paul I King Greece 1901-1964 x 20
Olav Glücksburg V King Norway 1903-1991 x 14
Ingrid Bernadotte Queen Consort Denmark 1910-2000 x 14
Philip Mountbatten Duke Edinburgh x 16
Queen Elizabeth II of the United Kingdom x 49
Sophia Glücksburg Queen Consort Spain 1938- x 38
Juan Carlos I King Spain 1938- x 10
Constantine II King Hellenes 1940- x 38
Carl XVI King Sweden 1946- x 24
King Charles III x 65
Diana Spencer Princess Wales 1961-1997 x 141
Great x 2 Grandfather: William Montagu
Great x 1 Grandfather: Simon Montagu 1st Baron Montagu
GrandFather: William Montagu 2nd Baron Montagu
Great x 1 Grandmother: Hawise St Amand
Father: William Montagu 1st Earl Salisbury
Great x 4 Grandfather: Henry Montfort
Great x 3 Grandfather: Thurstan Montfort
Great x 2 Grandfather: Peter Montfort
Great x 4 Grandfather: William Cantilupe Baron
Great x 3 Grandmother: Mabel Cantilupe
Great x 1 Grandfather: Peter Montfort
Great x 4 Grandfather: Adam Audley
Great x 3 Grandfather: Henry Audley
Great x 4 Grandmother: Emma Fitzorm
Great x 2 Grandmother: Alice Audley
Great x 4 Grandfather: Ralph Mainwaring
Great x 3 Grandmother: Bertrade Mainwaring
GrandMother: Elizabeth Montfort Baroness Furnivall Baroness Montagu
Philippa Montagu Countess March 1332-1381
Great x 1 Grandfather: Pierre Grandison
GrandFather: William Grandison 1st Baron Grandison
Mother: Catherine Grandison Countess of Salisbury 1304-1349
GrandMother: Sibylla Tregoz Baroness Grandison