diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
new file mode 100644
index 4347ad3..6bd3fc6
*** a/src/backend/utils/adt/formatting.c
--- b/src/backend/utils/adt/formatting.c
*************** DCH_to_char(FormatNode *node, bool is_in
*** 2640,2647 ****
  			case DCH_CC:
  				if (is_interval)	/* straight calculation */
  					i = tm->tm_year / 100;
! 				else	/* century 21 starts in 2001 */
! 					i = (tm->tm_year - 1) / 100 + 1;
  				if (i <= 99 && i >= -99)
  					sprintf(s, "%0*d", S_FM(n->suffix) ? 0 : 2, i);
  				else
--- 2640,2654 ----
  			case DCH_CC:
  				if (is_interval)	/* straight calculation */
  					i = tm->tm_year / 100;
! 				else
! 				{
! 					if (tm->tm_year > 0)
! 						/* Century 20 == 1901 - 2000 */
! 						i = (tm->tm_year - 1) / 100 + 1;
! 					else
! 						/* Century 6BC == 600BC - 501BC */
! 						i = tm->tm_year / 100 - 1;
! 				}
  				if (i <= 99 && i >= -99)
  					sprintf(s, "%0*d", S_FM(n->suffix) ? 0 : 2, i);
  				else
*************** do_to_timestamp(text *date_txt, text *fm
*** 3471,3497 ****
  		 */
  		if (tmfc.cc && tmfc.yysz <= 2)
  		{
  			tm->tm_year = tmfc.year % 100;
  			if (tm->tm_year)
! 				tm->tm_year += (tmfc.cc - 1) * 100;
  			else
! 				tm->tm_year = tmfc.cc * 100;
  		}
  		else
  			tm->tm_year = tmfc.year;
  	}
  	else if (tmfc.cc)			/* use first year of century */
- 		tm->tm_year = (tmfc.cc - 1) * 100 + 1;
- 
- 	if (tmfc.bc)
  	{
! 		if (tm->tm_year > 0)
! 			tm->tm_year = -(tm->tm_year - 1);
  		else
! 			ereport(ERROR,
! 					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
! 					 errmsg("inconsistent use of year %04d and \"BC\"",
! 							tm->tm_year)));
  	}
  
  	if (tmfc.j)
--- 3478,3511 ----
  		 */
  		if (tmfc.cc && tmfc.yysz <= 2)
  		{
+ 			if (tmfc.bc)
+ 				tmfc.cc = -tmfc.cc;
  			tm->tm_year = tmfc.year % 100;
  			if (tm->tm_year)
! 			{
! 				if (tmfc.cc >= 0)
! 					tm->tm_year += (tmfc.cc - 1) * 100;
! 				else
! 					tm->tm_year = (tmfc.cc + 1) * 100 - tm->tm_year + 1;
! 			}
  			else
! 				tm->tm_year = tmfc.cc * 100 + ((tmfc.cc >= 0) ? 0 : 1);
  		}
  		else
+ 		{
  			tm->tm_year = tmfc.year;
+ 			if (tmfc.bc && tm->tm_year > 0)
+ 				tm->tm_year = -(tm->tm_year - 1);
+ 		}
  	}
  	else if (tmfc.cc)			/* use first year of century */
  	{
! 		if (tmfc.bc)
! 			tmfc.cc = -tmfc.cc;
! 		if (tmfc.cc >= 0)
! 			tm->tm_year = (tmfc.cc - 1) * 100 + 1;
  		else
! 			tm->tm_year = tmfc.cc * 100 + 1;
  	}
  
  	if (tmfc.j)
diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
new file mode 100644
index ab8faab..db2cfe6
*** a/src/test/regress/expected/timestamp.out
--- b/src/test/regress/expected/timestamp.out
*************** SELECT '' AS to_char_3, to_char(d1, 'Y,Y
*** 992,998 ****
             | 1,997 1997 997 97 7 20 1 02 07 045 14 6 2450494
             | 1,997 1997 997 97 7 20 1 02 07 046 15 7 2450495
             | 1,997 1997 997 97 7 20 1 02 07 047 16 1 2450496
!            | 0,097 0097 097 97 7 01 1 02 07 047 16 3 1686042
             | 0,097 0097 097 97 7 01 1 02 07 047 16 7 1756536
             | 0,597 0597 597 97 7 06 1 02 07 047 16 5 1939157
             | 1,097 1097 097 97 7 11 1 02 07 047 16 3 2121778
--- 992,998 ----
             | 1,997 1997 997 97 7 20 1 02 07 045 14 6 2450494
             | 1,997 1997 997 97 7 20 1 02 07 046 15 7 2450495
             | 1,997 1997 997 97 7 20 1 02 07 047 16 1 2450496
!            | 0,097 0097 097 97 7 -1 1 02 07 047 16 3 1686042
             | 0,097 0097 097 97 7 01 1 02 07 047 16 7 1756536
             | 0,597 0597 597 97 7 06 1 02 07 047 16 5 1939157
             | 1,097 1097 097 97 7 11 1 02 07 047 16 3 2121778
*************** SELECT '' AS to_char_4, to_char(d1, 'FMY
*** 1063,1069 ****
             | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494
             | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495
             | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496
!            | 0,097 97 97 97 7 1 1 2 7 47 16 3 1686042
             | 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536
             | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157
             | 1,097 1097 97 97 7 11 1 2 7 47 16 3 2121778
--- 1063,1069 ----
             | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494
             | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495
             | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496
!            | 0,097 97 97 97 7 -1 1 2 7 47 16 3 1686042
             | 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536
             | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157
             | 1,097 1097 97 97 7 11 1 2 7 47 16 3 2121778
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
new file mode 100644
index 9a4ce3e..6581b5e
*** a/src/test/regress/expected/timestamptz.out
--- b/src/test/regress/expected/timestamptz.out
*************** SELECT '' AS to_char_3, to_char(d1, 'Y,Y
*** 1074,1080 ****
             | 1,997 1997 997 97 7 20 1 02 07 045 14 6 2450494
             | 1,997 1997 997 97 7 20 1 02 07 046 15 7 2450495
             | 1,997 1997 997 97 7 20 1 02 07 047 16 1 2450496
!            | 0,097 0097 097 97 7 01 1 02 07 047 16 3 1686042
             | 0,097 0097 097 97 7 01 1 02 07 047 16 7 1756536
             | 0,597 0597 597 97 7 06 1 02 07 047 16 5 1939157
             | 1,097 1097 097 97 7 11 1 02 07 047 16 3 2121778
--- 1074,1080 ----
             | 1,997 1997 997 97 7 20 1 02 07 045 14 6 2450494
             | 1,997 1997 997 97 7 20 1 02 07 046 15 7 2450495
             | 1,997 1997 997 97 7 20 1 02 07 047 16 1 2450496
!            | 0,097 0097 097 97 7 -1 1 02 07 047 16 3 1686042
             | 0,097 0097 097 97 7 01 1 02 07 047 16 7 1756536
             | 0,597 0597 597 97 7 06 1 02 07 047 16 5 1939157
             | 1,097 1097 097 97 7 11 1 02 07 047 16 3 2121778
*************** SELECT '' AS to_char_4, to_char(d1, 'FMY
*** 1146,1152 ****
             | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494
             | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495
             | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496
!            | 0,097 97 97 97 7 1 1 2 7 47 16 3 1686042
             | 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536
             | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157
             | 1,097 1097 97 97 7 11 1 2 7 47 16 3 2121778
--- 1146,1152 ----
             | 1,997 1997 997 97 7 20 1 2 7 45 14 6 2450494
             | 1,997 1997 997 97 7 20 1 2 7 46 15 7 2450495
             | 1,997 1997 997 97 7 20 1 2 7 47 16 1 2450496
!            | 0,097 97 97 97 7 -1 1 2 7 47 16 3 1686042
             | 0,097 97 97 97 7 1 1 2 7 47 16 7 1756536
             | 0,597 597 597 97 7 6 1 2 7 47 16 5 1939157
             | 1,097 1097 97 97 7 11 1 2 7 47 16 3 2121778