On 13 Jun 1349 [his grandfather] John Willoughby 2nd Baron Willoughby (age 46) died. His son [his father] John Willoughby 3rd Baron Willoughby (age 26) succeeded 3rd Baron Willoughby de Eresby. [his mother] Cecily Ufford Baroness Willoughby Eresby (age 22) by marriage Baroness Willoughby de Eresby.

He was buried at St James' Church, Spilsby [Map]. His wife [his grandmother] Joan Roscelyn Baroness Willoughby and Latimer (age 41) subsequently buried with him. She wears a skirt and mantle.

Before 29 Mar 1372 [his mother] Cecily Ufford Baroness Willoughby Eresby (age 45) died.

On 29 Mar 1372 [his father] John Willoughby 3rd Baron Willoughby (age 49) died. His son Robert Willoughby 4th Baron Willoughby (age 23) succeeded 4th Baron Willoughby de Eresby. [his wife] Margery Zouche Baroness Willoughby Eresby (age 33) by marriage Baroness Willoughby de Eresby.

He was buried at St James' Church, Spilsby [Map]. Early Plate Bascinet Period.

John Willoughby 3rd Baron Willoughby: In 1323 he was born to John Willoughby 2nd Baron Willoughby and Joan Roscelyn Baroness Willoughby and Latimer at Willoughby-on-the-Wolds. Before 1349 John Willoughby 3rd Baron Willoughby and Cecily Ufford Baroness Willoughby Eresby were married. When John married Cecily he changed his arms from Willoughby Arms to Willoughby de Eresby Arms. She the daughter of Robert Ufford 1st Earl Suffolk and Margaret Norwich Countess Suffolk.

Margery Zouche Baroness Willoughby Eresby: Around 1339 she was born to William Zouche 2nd Baron Zouche Harringworth and Elizabeth Ros Baroness Zouche Harringworth. Before 01 Oct 1369 Robert Willoughby 4th Baron Willoughby and she were married. On 18 Oct 1391 Margery Zouche Baroness Willoughby Eresby died.

After 16 May 1380 [his sister-in-law] Elizabeth Zouche (age 43) died.

On 28 May 1381 William Latimer 4th Baron Latimer of Corby (age 51) died. He was buried at Gisborough Priory [Map]. His daughter [his future wife] Elizabeth Latimer 5th Baroness Latimer, Baroness Neville and Willoughby (age 24) succeeded 5th Baroness Latimer of Corby.

On 23 Apr 1382 [his father-in-law] William Zouche 2nd Baron Zouche Harringworth (age 60) died. He was buried at Biddlesden Abbey, Buckinghamshire [Map]. His son [his brother-in-law] William Zouche 3rd Baron Zouche Harringworth (age 30) succeeded 3rd Baron Zouche Harringworth.

On 18 Oct 1391 [his wife] Margery Zouche Baroness Willoughby Eresby (age 52) died.

On 05 Nov 1395 [his wife] Elizabeth Latimer 5th Baroness Latimer, Baroness Neville and Willoughby (age 38) died. Her son [his step-son] John Neville 6th Baron Latimer of Corby (age 13) succeeded 6th Baron Latimer of Corby.

On 04 May 1396 [his former brother-in-law] William Zouche 3rd Baron Zouche Harringworth (age 44) died. He was buried at Biddlesden Abbey, Buckinghamshire [Map]. His son William Zouche 4th Baron Zouche Harringworth (age 23) succeeded 4th Baron Zouche Harringworth.

On 09 Aug 1396 Robert Willoughby 4th Baron Willoughby (age 47) died. His son [his son] William Willoughby 5th Baron Willoughby (age 26) succeeded 5th Baron Willoughby de Eresby. [his daughter-in-law] Lucy Strange Baroness Willoughby Eresby by marriage Baroness Willoughby de Eresby.